Well, being Pro-Israel is the default position for most politicians. It simply is in their best interest to be that way, especially Presidential candidates. It is an issue that predominantly has only one lean. It's politics, so money changing hands is always likely.
So naturally, when opposing voices or forces appear to counter the preferred direction of not just the US, there are consequences. Me talking like this would be considered anti Semitic. Mudslinging happens in the papers and on TV. Next election, the "anti Semitic" bastard gets sent packing.