AIPAC is done.
The campaigns against Bowman and Bush were desperation moves, and unless Israel pretty much instantly rights course and earns back some respect (which is certainly not going to happen at least as long as Netanyahu remains in office, or out of prison, for that matter), Israel's reputation is entirely deservedly going to continue to collapse, and more and more voters, and thus more and more politicians, are going to oppose them.
That would imply that AIPAC would have to work even harder and spend even more money, but I don't think that will work no matter what. Their crusades against Bowman and Bush have already left a bad taste in people's mouths, and rightly so, and it's near certain that in the not very distant future, it's going to flip, and the knowledge that AIPAC is funding opposition to a candidate will actually benefit that candidate - people will actually be more likely to vote for them because AIPAC opposes them. And that'll be the end of AIPAC.
And good riddance to bad rubbish.