There are several facts here people need to take notice of.

First, since the end of the Cold War, there has been very little real over-lap between the strategic interests of the United States and the interests of Israel. Support for Israel alienates Moslems, universally and in the region, and thus threatens stable access to fuel resources for the United States. The idea some attempt to sell, that the U.S. uses Israel to maintain access to and control of oil is risible.

Second, support for Israel is, in the domestic politics of the United States, becoming deeply tinged with fundamentalist Christian fanaticism, which leads increasingly to support for Israel being identified, among the general populace, with far right lunacy. It is worth noting many of these fundamentalist Christian supporters of Israel are, in actual fact, profoundly Anti-Semitic, in that they view Jews as having murdered Christ, and believe all Jews who do not convert to Christianity during the 'coming tribulations' will be killed as followers of the Anti-Christ. Their only real interest in Israel is the degree to which its existence is a prop in support of their beliefs in the imminent return of the Christ, and its attendant apocalyptic horrors and millenial reign of Jesus directly and physically over the earth. Israeli leaders who accept support from this element are making a contemptible bargain, that brings them into disrepute by association, rather like a candidate running on a 'law and order' platform would suffer by accepting an endorsement from a local Klavern.

Third, certain elements of cultural over-lap between the United States and Israel are fading away. One of the great unspoken facts of support for Israel here has always been the shared characteristics of a frontier/settlers society: we had Indians, they have Arabs, and expansion into a hostile frontier existence defined self-image of both societies to a fair degree. Fifty years ago popular culture here presented our expansion into the western plains as a fight between good White soldiers and settlers and bad, cruel Indians who above all could never be trusted. Today, these images are pretty much reversed, and the supply of people who grew up taking the former picture as an elemental frame of their moral universe and self-image as Americans is dwindling fast.