Purple wedding crackpot

[Dohor]

In LF's plot to murder Joffrey, there were three details that felt pretty weird: 

1. Crucial part of the plan were the poisoned amethysts in Sansa's hairnet, and getting them to Joffrey's cup required her to be sitting at the dais, so Olenna could get them without drawing too much attention. Sansa wouldn't have been at the dais if Tywin hadn't married her to Tyrion, and LF had no way of knowing about this in the end of ACOK, which is when Dontos gives Sansa the hairnet.

2. Why did LF and Tyrells need the hairnet at all? Why couldn't Olenna just take one amethyst with her to the wedding, and put it in Joff's cup when nobody was watching? 

3. Tyrells probably knew about LF trying to frame Tyrion for this, and they also knew that it would result in Sansa getting part of the blame, so why did Olenna want to marry her to Willas?

I'll try to make sense of these with this crackpot:

 

LF and the Tyrells were both at Bitterbridge during ACOK, where I think they started planning the Purple wedding. LF's motivations for this are: 1. Getting rid of Joffrey, so he wouldn't reveal LF's part in Ned's beheading. 2. Framing Tyrion, who might have enough intelligence to reveal LF's plans, and also good reason to do so. 3. Frame and then "rescue" Sansa so she won't have anywhere else to go but has to stay with LF. Tyrells want to make Marg the queen, but have her rather marrying Tommen, who is controlled much easier than Joffrey. And now comes the big part: Tywin was in their conspiracy too. He had already heard about Joffrey randomly executing Ned, and probably wants a less "willful" king, like Tommen. There is one question I really don't know how to answer, is how did LF dare to go talk Tywin about this? Because if the rest of this theory is true, it's LF who's the head conspirator, so it can't be like Tywin got the idea first. LF's skilled manipulator though, so perhaps he knew what to do. Anyway, let's move forward.

The reason I believe Tywin is in the conspiracy, is because he's the only person who could have known about Tyrion and Sansa marrying at the point when Sansa got the hairnet. If he, LF and Tyrells together planned the marriage together to frame Tyrion and Sansa for Joff's murder, she could easily have the hairnet during Sansa VIII ACOK, which was after Blackwater, when the entire conspiracy was already in KL. Their original plan was to kill Joffrey the way they did it, and then arrest Sansa, because in the public eye she has good motive for killing Joff, who tossed her aside to marry Marg. Then, during the arrest, someone would have "notice" the poisoned amethysts in the hairnet, and Sansa would have been thrown into dungeon, and get executed. 

The most important aspect of this theory is the fact, that Tywin and Tyrells don't entirely trust each other (No, they don't trust LF either, but they don't see him as an real threat, because of his low position that he still had at Bitterbridge). This means that both are discussing about the plan privately with LF, which gives him an opportunity to feed both of them different information. For Tywin, he doesn't tell about his jousting dwarf plan, which would make Tyrion look guilty. This accompanied with the fact that Tywin doesn't know about Cersei's paranoia towards Tyrion, and the fact that Tywin will judge Tyrion personally convinces Tywin to agree about framing Sansa, because he believes he can save Tyrion's skin. Now many of you are now probably thinking, why would Tywin want to kill Sansa who is both valuable hostage and "key to the north". Well, keep in mind, that he has most likely already planned both Red wedding and fake Arya plots, so he doesn't really need Sansa anymore, and is probably glad to give Starks their own Rains of Castamere by killing all the family members. 

But what does LF tell Tyrells? Well, they are lying to Tywin about framing Sansa. Their plan is to frame Tyrion with all the dwarf jousting and stuff, and have Dontos smuggle Sansa away to LF's ship, but instead of Fingers, it'll be going to Highgarden. Tyrells and LF, who don't know about Red wedding and are still seeing Starks as a serious threat to Lannisters, will hide Sansa there, and if Robb wins, they will prove their loyalty to him by showing him that they have been protecting his sister the whole time. Then the Stark-Tyrell allegiance will be confirmed by Sansa and Willas marrying. On the other hand, if Lannisters won, they could just "find" her and return her to Tywin. Tyrells naturally call this plan off when Red wedding happens and Sansa is no more of use to them. 

LF won't actually obey either of the plans, he was always going to do just like he actually did. If Tyrells had started questioning him when Sansa doesn't arrive at Highgarden, he would most likely have told Lannisters that his spies have noticed a treasonous Tyrell plot about saving Sansa Stark. 

When Olenna asked Sansa about Joffrey, that wasn't the start of Purple wedding's planning. She wanted a confirmation about Joffrey's nature, because she doesn't trust LF, and is also trying to get Sansa in the hiding-her-into-Highgarden plot. After all, if Joffrey is really that awful, it's totally reasonable to assume Sansa will side with Tyrells. Olenna tells LF what she did, but LF realizes this doesn't fit his plans, since he wants Sansa under his own influence, not that of Tyrells. This is why he tells Tywin about Tyrells wanting to marry Sansa off to Willas, but he presents the plot as Mace's idea. That is because Mace was never part of the Purple wedding plan, and LF cannot seed distrust between his conspiracy allies just now. When Tywin prevents Sansa-Willas marriage by marrying her to Tyrion, Olenna doesn't notice anything out of ordinary, since that's already part of the plan. 

Finally, few words about the dwarf jousting. Some people have said that it's unrealistic how LF knew exactly how everyone would react to it, but I don't think so. He probably just expected that drunken Tyrion would start threatening Joffrey, which would have made him look really guilty. All the cupbearer stuff was just a lucky coincidence for LF. 

[Bernie Mac]

18 minutes ago, Dohor said:

 And now comes the big part: Tywin was in their conspiracy too. He had already heard about Joffrey randomly executing Ned, and probably wants a less "willful" king, like Tommen.

With Mycrella in Dorne Tywin only has two claimants to the throne. He is not going to murder one of them after spending an entire war defending Joffrey against Robb Stark. Murdering his own grandson at the event that was securing the legitimacy of their win would have been idiotic, it would have made Tywin and the Lannisters look weak, it would have lost him the crown should the very young Tommen had an accident and sent the realm back into civil war. Tommen is still around half a decade (at least) from producing heirs and cementing the Throne. 

Is Tywin capable of murdering his own grandson? Certainly, but it would make more sense to do so after Joffrey had impregnated Margaery and after Stannis has been properly dealt with. It also would make more sense it happening at some other point rather than a Wedding Ceremony that the entire realm was watching, the Lannisters look weak for allowing the King to be assassinated in such a manner. 

[Lady Char]

My crackpot theory is that it was Tyrion's pie that was poisoned. Littlefinger and The Tyrell's were intending to remove Tyrion so they could marry Sansa to Willas. Its less risky than murdering Joff, in the sense that though the Lannister's would be angry that they lost Sansa's claim, neither Cersei or Tywin would be devastated by the loss of Tyrion.

Joff intercepted the pie.

[Dohor]

14 minutes ago, Bernie Mac said:

With Mycrella in Dorne Tywin only has two claimants to the throne. He is not going to murder one of them after spending an entire war defending Joffrey against Robb Stark. Murdering his own grandson at the event that was securing the legitimacy of their win would have been idiotic, it would have made Tywin and the Lannisters look weak, it would have lost him the crown should the very young Tommen had an accident and sent the realm back into civil war. Tommen is still around half a decade (at least) from producing heirs and cementing the Throne. 

Is Tywin capable of murdering his own grandson? Certainly, but it would make more sense to do so after Joffrey had impregnated Margaery and after Stannis has been properly dealt with. It also would make more sense it happening at some other point rather than a Wedding Ceremony that the entire realm was watching, the Lannisters look weak for allowing the King to be assassinated in such a manner. 

Actually, this made me rethink my theory, and I realized that Olenna took the amethyst from Sansa's hair when they were going to the wedding. This means Sansa never needed to be on the dais, and the theory works without Tywin.

How embarassing, should have thought about this more

 

[Light a wight tonight]

1 hour ago, Lady Char said:

My crackpot theory is that it was Tyrion's pie that was poisoned. Littlefinger and The Tyrell's were intending to remove Tyrion so they could marry Sansa to Willas. Its less risky than murdering Joff, in the sense that though the Lannister's would be angry that they lost Sansa's claim, neither Cersei or Tywin would be devastated by the loss of Tyrion.

Joff intercepted the pie.

The problem here is that the Lannisters had Sansa under their control and through her control of the North. They wouldn't have allowed the Tyrrells to marry her to Willas or anyone else outside the Lannister family, and there were plenty of eligible young Lannister men available, Lancel and Daven just to name two. Simple politics.

[Lady Char]

3 minutes ago, Light a wight tonight said:

The problem here is that the Lannisters had Sansa under their control and through her control of the North. They wouldn't have allowed the Tyrrells to marry her to Willas or anyone else outside the Lannister family, and there were plenty of eligible young Lannister men available, Lancel and Daven just to name two. Simple politics.

You are right. The more I think on it, it wouldn't make any sense. The plan was definitely to smuggle her out to Littlefinger. So he must have promised them something else as payment.

[Dohor]

5 minutes ago, Light a wight tonight said:

The problem here is that the Lannisters had Sansa under their control and through her control of the North. They wouldn't have allowed the Tyrrells to marry her to Willas or anyone else outside the Lannister family, and there were plenty of eligible young Lannister men available, Lancel and Daven just to name two. Simple politics.

I agree, this is exactly why I think my crackpot about LF's and Tyrell's plans works. 

I still think that there was some third party in the purple wedding conspiracy alongside LF and Tyrells, it just wasn't Tywin. This third party wanted Sansa dead, and LF and Tyrells were trying to convince him/her/them/whatever that they are framing Sansa. Otherwise they wouldn't have bothered with the whole hairnet thing.

[Light a wight tonight]

21 minutes ago, Lady Char said:

You are right. The more I think on it, it wouldn't make any sense. The plan was definitely to smuggle her out to Littlefinger. So he must have promised them something else as payment.

Could be some added inducement, or just that Lady O knew that Joffrey would at some time start abusing Margaery, and that hot-headed King's Guard Loras, who was very protective of his sister, would kill Joff for that, leading to his own execution. Better to wed Marg to the next available candidate for the Iron Thone.

[Chris Mormont]

The Purple Wedding has always fascinated me because I do not believe all is what it appeared.  For example,

Tyrion was not framed, there is no way LF could have predicted that Joff would make Tyrion his cup bearer during the wedding, which ultimately gave him the opportunity to poison Joff. 

I think the hairnet was just a ruse, so LF could have something to hold over Sansa as he rescued her.

Why did Joff only show signs after eating Tyrion's pie?

Too many moving parts for anyone to have predicted that Tyrion would get the blame.  I think it was LF's intention all along for Sansa to get blamed so she would always be indebted to him for saving her.

[Light a wight tonight]

3 hours ago, Dohor said:

In LF's plot to murder Joffrey, there were three details that felt pretty weird: 

1. Crucial part of the plan were the poisoned amethysts in Sansa's hairnet, and getting them to Joffrey's cup required her to be sitting at the dais, so Olenna could get them without drawing too much attention. Sansa wouldn't have been at the dais if Tywin hadn't married her to Tyrion, and LF had no way of knowing about this in the end of ACOK, which is when Dontos gives Sansa the hairnet.

2. Why did LF and Tyrells need the hairnet at all? Why couldn't Olenna just take one amethyst with her to the wedding, and put it in Joff's cup when nobody was watching? 

3. Tyrells probably knew about LF trying to frame Tyrion for this, and they also knew that it would result in Sansa getting part of the blame, so why did Olenna want to marry her to Willas?

As to the points:

 1 Olenna got the amethyst before they got to the dias, IIRC.

2 The hairnet was needed to link Sansa to the poisoning. It certainly would have been simpler for LF just to hand off a Strangler crystal to Olenna at the wedding negotiations. But LF needed some leverage to get Sansa to willingly flee, since she's just been enduring everything passively up to that point.

3 Was the plan to marry Sansa to Willas still in effect at the time? Didn't look like it. The Lannisters put the kibosh on it and Olenna just threw Sansa under the bus after that.

[Dohor]

9 minutes ago, Light a wight tonight said:

As to the points:

 1 Olenna got the amethyst before they got to the dias, IIRC.

2 The hairnet was needed to link Sansa to the poisoning. It certainly would have been simpler for LF just to hand off a Strangler crystal to Olenna at the wedding negotiations. But LF needed some leverage to get Sansa to willingly flee, since she's just been enduring everything passively up to that point.

3 Was the plan to marry Sansa to Willas still in effect at the time? Didn't look like it. The Lannisters put the kibosh on it and Olenna just threw Sansa under the bus after that.

1. Realized that right after submitting this, my bad.

2. But wasn't Sansa going to escape with Dontos anyway? The hairnet really did nothing to convince anyone of her guilt, it was more the facts that she disappeared right after the murder and that she's Tyrion's wife.

3. This question only raised to me just after I had made most of this theory, so it can make perfect sensa without me crackpotting. I guess I put this one in wrong place.

Shit, I just remembered that Sansa told Dontos about the Willas thing, and my entire theory about LF and Tyrells trying to smuggle Sansa to Highgarden was based on me not realizing how LF knew about Willas. So now I have succeeded to undermine every point that makes my theory relevant.

So basically now this little crackpot makes sense if you remove Tywin taking part, but the story makes just as much sense without it. I'm still confused about the hairnet though...

[Bernie Mac]

57 minutes ago, Chris Mormont said:

 

Too many moving parts for anyone to have predicted that Tyrion would get the blame.  I think it was LF's intention all along for Sansa to get blamed so she would always be indebted to him for saving her.

Tyrion had publicly hit Joffrey, had threatened his life and had confiscated all of Pycelle's belongings (including poisons). 

Tyrion, with both the clearest motive and the obvious means, was always going to be the prime suspect in his nephew's death. 

[Therae]

16 minutes ago, Dohor said:

 

So basically now this little crackpot makes sense if you remove Tywin taking part, but the story makes just as much sense without it. I'm still confused about the hairnet though...

I think the hairnet thing was, as @Chris Mormont said, more about manipulating Sansa herself; she realizes she was probably an accessory by way of the hair net, so she believes she is implicated, so she doesn't balk at running, which actually does implicate her without any hairnet required.

But then the hairnet was in place very early--Dontos gave it to her in CoK Sansa VIII--and I believe Tyrion was actually still out of commission at that time, courtesy of Mandon Moore, so it may well have just been the case that LF couldn't predict Tyrion's availability as a patsy, and the hairnet ensured that there was evidence to use against Sansa no matter what happened.

[Kandrax]

Tyrell's baker tried to poison everyone with pie.

[John Suburbs]

@Dohor, I tried like five times to craft a response to your OP, but I couldn't because the premise is just off. Nobody was trying to kill Joffrey with wine, they were trying to kill Tyrion with pie.

Joffrey's death makes no sense for anyone involved. There is an assumption that every character in the book is so horrified by Joffrey's actions that they'll do anything to take him down, and this is simply untrue. The Tyrells, for one, backed the Mad King long after he was burning high lords with wildfire in the throne room and having their sons strangle themselves trying to help. Tywin himself has committed atrocities far worse than Joffrey, including diminishing his house's own political and military clout by exterminating two of his most powerful vassal houses. And Littlefinger is literally one of two people (the other being Margaery) who have demonstrated an ability to manipulate Joffrey, which makes him (Joff) LF's and Lady O's most valuable piece in the Game of Thrones. Killing him would be like taking your dragon off the cyvasse table and chucking it into the sea.

LF delivered the hairnet when and how he did because there was no other safe option. The lingering chaos after the battle provides the perfect cover, and he might not be able to deliver it later. He can't give it to Dontos or anyone else because they could either sell it and split or, worse, use it to betray Littlefinger. Sansa doesn't know what it is, just that is her salvation. So at this point, LF only needs to make sure that Sansa, the poison and the eventual target are in the same place at the same time no matter how or when he chooses to use it.

So, no, there is no reason to think Tywin was in on the plan just because of the hairnet. The decision to marry Sansa to Tyrion was not made until after the Willas plan was exposed. Which itself is problematic with your theory because if Lady O is in on the plot at this point, then why is she trying to marry to Sansa to Willas when she will either be gone after the assassination or its prime suspect? And wouldn't Sansa be at least allowed to tell her story before they chop off her head, including how she got the hairnet, who fiddled with it just before the feast...? Plus, we also have the problem of why Lady Olenna is intentionally making it more difficult to poison Joffrey, and just Joffrey, by providing a huge chalice that is difficult to reach no matter where it is and would reasonably be shared by both the bride and groom at this point in the feast when toasts are made?

There's a whole lot more to this, so I'll just ask you to reread the whole scene again with the poison in the pie. Literally everything falls into place: the physical facts of both poisonings, the logistics of getting the poison to Tyrion, the motivations of the only two principal plotters, Lady O and Littlefinger, as well as all the events that led up to the wedding and followed as well. To do the wine, virtually everyone involved -- people who have been shown to be crafty, experienced GoT players -- need to be making the most absolutely stupidest decisions imaginable, and the plot itself requires an entire sequence of utterly unpredictable events to succeed. The pie, meanwhile, needed only one utterly unpredictable event to fail.

On ‎2‎/‎27‎/‎2018 at 0:50 PM, Lady Char said:

You are right. The more I think on it, it wouldn't make any sense. The plan was definitely to smuggle her out to Littlefinger. So he must have promised them something else as payment.

No worries, you're on the right track. The Tyrells have no reason to kill Joffrey because a) he is no threat the Margaery and b ) if he does eventually turn on her or proves to be an unbearable king they can get rid of him in all sorts of ways that do not involve killing him in front of a thousand witnesses at a time when the entire Tyrell family is in the Red Keep surrounded by Lannister guards. And by then, of course, Margy will have already birthed the new heir to the Iron Throne so Joffrey's death would mean Margaery becomes Queen Regent until her son comes of age. This could happen within two years or less and is a far better outcome than trying to manipulate Tommen when he ascends the throne five years from now.

It is also unlikely that Lady O does not know about the plan to use the killing to cover Sansa's escape. Just killing Tyrion doesn't help them a whole lot, since Tywin would just marry Sansa off to another Lannister. The goal here is not to rescue Sansa but to prevent Tywin from putting his heir on the high seat in Winterfell. Of course, she would prefer to have Sansa in Highgarden, but with the Willas plan undone, thanks to Littlefinger, she was forced to choose the lesser of two evils.

[Prince of the North]

Well, in the interest of full disclosure here's what Martin himself has to say on the subject of Joffrey's murder:

Quote

In an upcoming Rolling Stone interview with George R.R. Martin, the writer behind the popular Game of Thrones novels offers the following comments during a discussion of whether his characters’ deeds can be redeemed: 

Martin: Who kills Joffrey? 

Rolling Stone: That killing apparently happens early in this fourth season. The Song of Ice and Fire books, of course, are well past the poisoning of King Joffrey. 

Martin: In the books — and I make no promises, because I have two more books to write, and I may have more surprises to reveal — the conclusion that the careful reader draws is that Joffrey was killed by the Queen of Thorns, using poison from Sansa’s hair net, so that if anyone actually did think it was poison, then Sansa would be blamed for it. Sansa had certainly good reason for it.

The reason I bring this up is because I think that’s an interesting question of redemption. That’s more like killing Hitler. Does the Queen of Thorns need redemption? Did the Queen of Thorns kill Hitler, or did she murder a 13-year-old boy? Or both? She certainly had good reasons to remove Joffrey. Everything she’d heard about him, he was wildly unstable, and he was about to marry her beloved granddaughter. The Queen of Thorns had studied Joffrey well enough that she knew that at some point he would get bored with Margaery, and Margaery would be maltreated, the same way that Sansa had been. Whereas if she removed him then her granddaughter might still get the crown but without all of the danger. So is that a case where the end justifies the means? I don’t know. That’s what I want the reader or viewer to wrestle with, and to debate. 

So, here Martin definitively answers:

Who killed Joffrey? "Joffrey was killed by the Queen of Thorns"

How was Joffrey killed? "...using poison from Sansa’s hair net"

Why was the poison in Sansa's hair net? "...so that if anyone actually did think it was poison, then Sansa would be blamed for it. Sansa had certainly good reason for it."

Why was Joffrey killed? "She [the Queen of Thorns] certainly had good reasons to remove Joffrey. Everything she’d heard about him, he was wildly unstable, and he was about to marry her beloved granddaughter. The Queen of Thorns had studied Joffrey well enough that she knew that at some point he would get bored with Margaery, and Margaery would be maltreated, the same way that Sansa had been. Whereas if she removed him then her granddaughter might still get the crown but without all of the danger."

And, most importantly, what he [Martin] wanted readers to "wrestle with, and to debate" after reading it: The reason I bring this up is because I think that’s an interesting question of redemption. That’s more like killing Hitler. Does the Queen of Thorns need redemption? Did the Queen of Thorns kill Hitler, or did she murder a 13-year-old boy? Or both? So is that a case where the end justifies the means? I don’t know. That’s what I want the reader or viewer to wrestle with, and to debate. 

This is very good information for people to factor in as they speculate about the Purple Wedding.    

[Dorian Martell's son]

On 2/27/2018 at 8:04 AM, Dohor said:

In LF's plot to murder Joffrey, there were three details that felt pretty weird: 

1. Crucial part of the plan were the poisoned amethysts in Sansa's hairnet, and getting them to Joffrey's cup required her to be sitting at the dais, so Olenna could get them without drawing too much attention. Sansa wouldn't have been at the dais if Tywin hadn't married her to Tyrion, and LF had no way of knowing about this in the end of ACOK, which is when Dontos gives Sansa the hairnet.

Olenna only needed to pass by sansa to get the crystal, and as the only surviving daughter of winterfell, she would be at the wedding, hostage status or not.  

On 2/27/2018 at 8:04 AM, Dohor said:

2. Why did LF and Tyrells need the hairnet at all? Why couldn't Olenna just take one amethyst with her to the wedding, and put it in Joff's cup when nobody was watching? 

 Littlefinger needed a way to get the poison to Olenna, and, as a pov story, sansa's involvement would be needed to see any of the plot. Otherwise, it would just happen without the reader seeing any of it. She shows up, Joff dies and that is it. Dontos, Olenna, Littlefinger, Tyrion, all of them interact with her, and that is how we see it 

On 2/27/2018 at 8:04 AM, Dohor said:

3. Tyrells probably knew about LF trying to frame Tyrion for this, and they also knew that it would result in Sansa getting part of the blame, so why did Olenna want to marry her to Willas?

Olenna wanted her to marry Willas so her family would have a claim to winterfell. With Rickon, Bran and Robb dead, the heir of Sansa and Willas would be the heir to the north. That is a big chunk of real estate. 
So, there is no need for any crackpot or tinfoil hats for the story to work as written and explained 

[Prince of the North]

1 hour ago, Dorian Martell's son said:

 Littlefinger needed a way to get the poison to Olenna, and, as a pov story, sansa's involvement would be needed to see any of the plot. Otherwise, it would just happen without the reader seeing any of it. She shows up, Joff dies and that is it. Dontos, Olenna, Littlefinger, Tyrion, all of them interact with her, and that is how we see it 

This.  And, of course, when one is going to commit murder having a patsy in place is a very, very good idea

[Nevets]

21 hours ago, John Suburbs said:

Joffrey's death makes no sense for anyone involved. There is an assumption that every character in the book is so horrified by Joffrey's actions that they'll do anything to take him down, and this is simply untrue. The Tyrells, for one, backed the Mad King long after he was burning high lords with wildfire in the throne room and having their sons strangle themselves trying to help. Tywin himself has committed atrocities far worse than Joffrey, including diminishing his house's own political and military clout by exterminating two of his most powerful vassal houses. And Littlefinger is literally one of two people (the other being Margaery) who have demonstrated an ability to manipulate Joffrey, which makes him (Joff) LF's and Lady O's most valuable piece in the Game of Thrones. Killing him would be like taking your dragon off the cyvasse table and chucking it into the sea.

There is so much wrong with this I don't know where to begin.

Yes, the Tyrells backed the Mad King despite his actions.  They also remember how his reign ended; with civil war and the death and exile of his entire family.  Given that the Tyrells would be the closest family, I doubt they are anxious to repeat the experience.  And Joffrey is a very unpredictable, moody, and erratic ruler with a serious penchant for cruelty.  Not someone you want as a ruler.

Yes, Tywin has done some pretty bad stuff.  But he is more of a Macchiavellian ruler: ruthless but pretty predictable.  Don't cross him and you'll be fine.  And it takes quite a lot to really anger him.  Unlike Joffrey, who lets his whims take the dya

Sansa's visit would have filled the Tyrells with unease.   Not only does she confirm the stories they have heard about Jorffrey, her demeanor is worrisome as well.  She is scared spitless just to be talking with them.  And that isn't really normal and suggests unpleasant undercurrents.  And as to whether Margaery would be in any danger, they (and we) don't really know.  He could very easily become an abusive husband, and unlike some families, the Tyrells seem quite closely-knit.  I can't quite see hot-headed Loras idly standing by while his sister is used as a punching bag, for example

And there is Tommoen in the wings.  He is sweet and malleable.  This is different from being manipulable.  YOu may be able to manipulate Joffrey, but you don't know what you will get.  (By the way, when did we see Margaery manipulate him?).  Tommen cn be shaped, and they can hope for a years-long regency into the bargain.  

I see plenty of reasons for the Tyrells to want Joffrey dead.  I see few if any reasons for them to want Tyrion, dead, though.  

[Ygrain]

On 27. 2. 2018 at 5:04 PM, Dohor said:

LF's motivations for this are: 1. Getting rid of Joffrey, so he wouldn't reveal LF's part in Ned's beheading.

I believe his motives were several and a bit more complex, but this is very likely one of them.

On 27. 2. 2018 at 5:04 PM, Dohor said:

2. Framing Tyrion, who might have enough intelligence to reveal LF's plans, and also good reason to do so

Add to it that Tyrion 

1) messed with LF in his little scheme to find out who Cersei's informer was,

2) became Master of Coin and possessed the intelligence to find out about LF's financial machinations

3) knew that LF had framed him for the attempt on Bran with the false claim about the dagger

4) married Sansa

So LF arranged for the jousting dwarves, who, along with Tyrion's big mouth, were bound to cause some very public and  hostile exchange between him and Joffrey, so that everyone knew that Tyrion hated Joffrey's gut. Then there is the damning testimony of Taena Merryweather, whose motive we know nothing about so far... Tyrion was as good as dead, and no-one would ever suspect that LF might have wanted him dead. Ingenious.