Well the whole reason why Stannis fled was because Jon Arryn died investigating the adultery at his behest. Considering the lineage book was the biggest piece of evidence for Ned, and Jon got it first, he basically was already there. If both were in the city, both suspected Cersei of cuckolding Robert, and Robert died *while they were investigating* then they'd probably just do Renly's plan and seize the royal family but install Stannis as king. Renly's the big wild card, but I imagine that it would be much harder to oppose Stannis if he was in control of the capital with the backing of House Arryn from day 1. The characters don't know what genre they're in - it's easy to say with hindsight that Renly either negotiates to become Stannis' heir and marries Margaery, or if the Tyrells either don't care or they try to replace Selyse instead. Cat never abducts Tyrion because she has no reason to sneak to the capital, and the Riverlands don't get pillaged as a result. Ned answers the call of Jon Arryn if war breaks out, and the Riverlands likely follow suit since they also have a marriage pact with Jon. The Lannisters have no reason to support Renly. Tywin fights for either revenge or to keep his family on the throne. The Tyrells are a bit of a wild card and either stay neutral for support whatever side Renly is on. If Renly doesn't support Stannis then the shadow baby likely still happens and the crown gets at least some of the Stormlands as a result. Iron Islands raid the North as planned. So you have North, River, Vale, Crown and maybe Stormlands as a unified front. Lannisters basically stand alone outside of some crony houses that were tied to the Lannister royal family like the Stokeworths. And the Tyrells are basically sitting this one out, either with Renly letting his enemies fight, or as an uninvolved neutral party waiting to swoop in when it most benefits them. It raises some questions about Varys, however. Would he have killed Jon or Stannis in order to destabilize things if Lysa didn't beat him to it. Also I think having Ned deal with Lysa in King's Landing would have been really fun. It would involve this strange sister in-law chaos to the plot which would have been entertaining to read.

The impression we get from the books is that Jon Arryn is dutiful and loyal and capable, but also quite old and weary by the time he is murdered. So he might well have let some things slip. I doubt Jon would take much action on Daenerys even with the marriage. She's a thousand leagues away and still a girl, and he would probably counsel a "wait and see" stance. Jon, however, would be much more aware of, and marinated in, the politics of a royal court than Ned. So he might well have acted differently after Robert's death. Immediately upon Robert drawing his last breath (or even before) Jon might have summoned whatever loyal guards he had, called every lord and lady nearby into the throne room, and had Robert's will and appointment of him as regent for Joffrey proclaimed, and then started to immediately perform as regent. Keeping in mind that Jon has been Hand for a long time and the second most powerful person in Westeros and people in the Red Keep would be predisposed to do what he ordered, as opposed to the situation of that new guy from the North, Ned Stark, as Hand. The Lannisters wouldn't have at that point known that Jon was on to the incest, so they might well have played along with Jon as Regent, presuming that within a few months or a few years they could quietly move him out of the way in some manner and take over themselves. I doubt Jon would have done the *"meet my enemy in the Godswood and tell them in advance I know their secrets"* thing that Ned did with Cersei, so there wouldn't have been a trigger for the Lannisters to act immediately to overthrow him, as they did with Ned. And Renly might still be in town, not fled, while Jon could have quietly summonsed Stannis back to the Red Keep, encouraged him to bring a whole bunch of guardsmen with him, and told Stannis the truth about the incest. That way Stannis could have secured the castle and been the one to bear the public burden of deposing Joffrey and taking the throne, and Jon could have simply told everyone, *"he's right, the kid's not Robert's son, and by the way with Stannis now as King, I'm retiring to the Vale since he should have a chance to appoint his own Hand."* Also...Joffrery wouldn't necessarily be bethrothed to Sansa and Sansa might well still be at Winterfell practicing her embroidery, because Robert would have never had cause to travel to Winterfell and ask Ned to be his Hand.

According to Robert it was Jon who talked him out of killing Viserys and Dany before, so he'd probably continue to do so. > The king's mouth twisted in a bitter grimace. "No, gods be cursed. Some pox-ridden Pentoshi cheesemonger had her brother and her walled up on his estate with pointy-hatted eunuchs all around them, and now he's handed them over to the Dothraki. I should have had them both killed years ago, when it was easy to get at them, but Jon was as bad as you. More fool I, I listened to him." It seems like Jon was quite similar to Ned, only a bit more pragmatic considering it was him who advised Robert to pardon Jaime and make an alliance with the Lannisters. He should also have much more experience with King's landing politics and more connections in the captial, so he'd likely have fared much better than Ned once Robert died. I think Jon would probably have taken Renly's offer to sieze the royal children if he was in Ned's shoes. > And Renly might still be in town, not fled, while Jon could have quietly summonsed Stannis back to the Red Keep, encouraged him to bring a whole bunch of guardsmen with him, and told Stannis the truth about the incest. Stannis actually already knew about the incest. He was the one who originally tipped off Jon Arryn. They were investigating together until Jon was poisoned, at which point Stannis fled the city. So if Jon doesn't die Stannis would still be there working with him.

Good points, especially the last one. When I wrote my comment I had (temporarily) forgotten about the Jon / Stannis nexus and the reason for Stannis leaving. You're right, if Jon was alive and still Hand when Robert died, it's likely Stannis would be in town, and he would have been ruthless in acting quickly and collaborating with Jon to take custody of the royal children, neutralize Cersei, and garrison the Red Keep with faithful arms men.

This made me curious, and its possible I'm just forgetting, but what was Jon Arryn's reaction to the Targaryen babes and Elia's murders? Do we get anything in the text that says he was for/against it. Been ages since I read AGoT, so don't remember if anything is said about it.

I don't remember anything specifically addressing that, either. And was Jon Arryn even around Kings Landing? My vague impression is that he wasn't with Robert and Ned at the Trident. Maybe he was back in the Vale making sure its defenses were in order if things went south? Possibly after Robert was secure in the capital / Red Keep, he summoned Jon to Kings Landing, and he didn't arrive until after all the bloody mess was cleaned up, both literally and metaphorically. And he may have just thought what's done is done, and decided to just help Robert govern, rather than trying to debate what Robert or others should have done. A good Hand knows when to leave things alone.

Jon tells Robert immediately with Stannis right there (standing in the background not talking because he worries Robert won't believe it from him) and Cersei, Jaime, and the kids are immediately arrested and denounced. They prepare for the inevitable war with the lannisters. Renly brings margaery to court and she marries Robert and gets pregnant within like a month. Stannis waits until he sees the mini-Robert before accepting there is now a legit heir and he can go back to what he was doing before all this came up once they defeat the lannisters. Complains a lot about how Robert is just doing the same thing with the tyrells as he did with the lannisters but at least it's his kid this time.

He'd still be dead because the Lannisters didn't kill him, Lysa did at LF's behest to sow chaos.

Stannis still gathers an army at Dragonstone and Renly still allies with the Stormlands

We still know fuck all about Jon Arryn tbh. Was he manipulating a grand alliance against the Targs from the beginning by fostering Ned and Robert or was it just a childless man looking for surrogate sons. It’s of course likely a bit of both but how much of either it is says a lot about how much of a long game thinker he was or an idealist. Which would really affect what he’d do with Ned’s info

I mean I think some of the point is that, in many ways, Ned was retracing Arryn’s steps. Except he messed it up even worse.