Galloway is a self-aggrandizing jackass who will align himself with anyone who ...snip...
I agree with the part of your starting sentence I've snipped but I would say "Galloway is a self-aggrandizing jackass who will align himself with anyone who will give him publicity."
He's wants the publicity and the money/fame that comes from it. I've seen very little evidence for example that he is even a good constituency MP never mind a good politician.