I'm certainly not advocating it, but for the sake of interesting discussion, what do you suppose WOULD happen if the U.S. left Israel to its own devices?
Then it would be an evenly matched fight resulting in millions of civilian deaths on both sides and would likely involve nuclear weapons. By simple attrition, Israel would be defeated and Islam would continue its expansion into Africa, Europe, India and the Phillipines.
The simple superiority of the Israeli military prevents a much larger conflict.
They'd own all of the middle east.