This is very interesting, and judging by a skim-read of his wikipedia bio somewhat plausible. It was vague on exactly why he decided to return to Israel, though. Does anyone know more?
However, I think he'd have a tough time getting elected to the Senate from Massachusetts. The House might be more plausible if he could find the right district. In the House he'd definitely be a leading advocate for Israel, but I'm not sure that would provide him with a sufficient platform to become SecState. Ambassador to Israel is more plausible.
Actually, I think the most interesting scenario would be for him to be elected Governor of Massachusetts.