First I think there is a mix in the quoted argument between US backing and the US 'aid'.
The US 'aid' is basically a Money that the US allocate to Israel but that Israel can only spend it on US arms. So basically form the US perspective it is more an aid to their arms industry. And for Israel this is a double edge sword, since Israel could really supply itself with almost anything she buys from the US, and than offer her arms for export, making profit and competing with American suppliers. Moreover the 2.5-3bUS$ of this aid is less than 5 percent of our budget and we could really manage without it.
As for the backing- I think it is more like holding us back, than backing us. Israel has the military might to crush all her neighbors. If she hadn't been militarily superior than no US backing would save her, I do not expect American troops to fight our wars. If the US would just free us from the short leash we'd do fine. Of course the US can destroy Israel by herself or help the Arabs and the Iranian Nazis to destroy us by switching sides, by arming them and boycotting us. But the Muslims on their own cannot defeat us.