Israel's continued existance is of national interest to many governments. They're an important political ally, critical to the stability in the region and the a

Israel's continued existance is of national interest to many governments. They're an important political ally, critical to the stability in the region and the ability of the west to project power into the middle east. Also keep in mind that much of that money flows back to the US. Overall this is a small investment in ensuring that Israel is so incredibly well defended that nobody in the surrounding area could ever come close to believing they have a chance against them.