Their so-called support for Israel isn't based on some sense of responsibility out of respect for the originations of their Judeo-Christian heritage. It is catering to the right-wing, neo-c0n, fundamentalist Christian coalition of their party which salivates at every chance we get to go to war in the Middle East. There has been a very powerful alliance with the chickenhawks and the likes of Ralph Reed/Christian Coalition, Pat Robertson and others who have a bizarre "End Times" fantasy involving the return of Christ which requires a massive conflict in the Middle East first.
If you believe in the omnipotent power of an Almighty Being, then it is presumptuous to think that you can somehow alter or expedite a master plan that has already been predetermined. Yet, that is what these people think. They cheer for every war that possibly brings us closer to WWIII and the return of their blond-haired, blue-eyed Jesus through this scenario which was never really outlined in the Bible. They believe in an Apocalypse which involves the rebuilding of the Temple and the formation of the Jewish state over 60 years ago plays into the script they've created.
The religious right supports the expansion of settlements in areas already deemed to belong to the Palestinians. They cheer at every clash between the IDF and stone-throwing youths or anything else that brings things closer to the boiling point. It is really a sick, sick little enabling/fantasy combination that keeps the conflict going. This isn't really a war over territorial rights, or a conflict between mainstream Judaism and Islam. It is a proxy war fought between radical Christianity and radical Islam, pitting the hardline Jews against hardline Muslims, in hopes of igniting a religious "Final Solution" in which Christ returns to Earth, but not before we Jews are slaughtered or converted to their religion.
I've had other Jews laughingly tell me that they think these Christians are idiots but they are more than happy to keep taking their money. If it wasn't responsible for years of war, and millions of deaths, this little fantasy would be one I would laugh at. Hell, if I had religious fanatics handing me money and support because of some bizarre dream they had, I'd gladly take their money also. This isn't a laughing matter though, especially when you have these folks being tricked into voting for candidates who support wars that will never actually bring back Christ, but quite possibly the end of the world as we know it. It could end in an Apocalypse, but not the one they want. Dear Jesus, I really like you but your followers scare the hell out of me.