America, in fact, has a history of subordinating Israeli security to its own perceived interests - from embargoing arms during the War of Independence to bullying Israel out of the Sinai in '56 to letting Egypt close the Strait of Tiran in '67 to rescuing the PLO in Beirut in '82, all the way to the present hudna that has rescued Hamas from Israel's offensive and allowed it to regroup and rebuild - and those are just a few examples. No doubt, the U.S. is Israel's only ally and gives it extensive military, economic, and diplomatic support. But it tries to balance that by looking out for its own, primarily economic interests in the Arab world.
Maybe, as the US experiences in Iraq some of what Israel lives with every day, America will be a little more sympathetic to the Israeli viewpoint and will begin to expect a little bit more from the Arabs. Sometimes balance is detrimental to progress.