How likely are AAA-PBP to split back into their constituent parts after the election? Alternatively, how likely are they to merge permanently? In fact, what are the differences between them?
1) Extremely likely, they have before
2) Too many obstacles of personality and organization for that
3) They belong to different socialist 'internationals' and the PBP is a front name for the Socialist Workers Party (SWP) a group famous for entryism and trying to take over organizations.
To add a bit more, the CWI (SP's international, of which I am a former member) had a big fight in the 90s over entryism (it was Militant's international) and ended up pretty much denouncing the practice.