A better question: Who or what is to stop Israel from taking and occupying more land from Syria, Jordan, and Egypt? Not that they would, mind you.
I've often thought about those questions myself...but I'll do you one better. Why isn't Israel playing a much larger role in Iraq? If I'm interpreting all the evidence that has been presented showing all of Saddam's WMD's,(Iraq does not have ICBM technology) isn't Israel (and perhaps Turkey) the one nation that is in the most immenant danger? And you can't use the world opinion or U.N. opinion excuse, we all know that they are irrelevant.
Good question. Israel is "our friend and ally in the Middle East" and "our strategic partner in the Middle East", but we have yet to take full advantage of that fact.
Why not? IMO, we can't. Israel assisting the US in an action against an arab state would be seen as the US assisting Israel in warring against the arabs.
This is evidenced on a smaller scale whenever Israel uses US-made jets against the terrorists; big hue and cry about how the US is assisting "the jews" in "wiping out" the arabs.
Quite frankly, Turkey, Kuwait, and Saudi Arabia are more helpful. Not to say that Israel isn't helping on the QT.