To an extent, it is a matter of “in for a dime, in for a dollar”.
There was doubt and speculation at first as to whether the Truman Administration would even recognize the State of Israel.
Once it did, the U.S. found it had to keep taking action to back up its support for a nation which is in an extremely precarious position, even as that support became more and more expensive and, at time, more and more difficult to defend.
The U.S. has a striking history of turning on nations which are not part of the trilateral alliance if it suits our purpose. Noreiga in Panama was an ally of the U.S. not too long before we invaded and ousted him. Saddam Hussein received military and other support from the U.S. throughout his war with Iran.
It is true that Israel is the only genuine democracy in its region, and the failure of America to support such a democracy would be odious to a great many Americans. At the same time, though, commitment to fostering and upholding democracy abroad has never been a significant factor in guiding American foreign policy; we have supported police states throughout the world when it has served our purpose.
But in the case of Israel, the U.S. government quickly found it would be very, very difficult to let our commitment to the nation, and its democratic system, falter. This is largely because of the strong pro-Israel lobby in the United States.
For centuries talk of Jewish conspiracies have been the easy recourse for crazy bigots of every stripe, and this makes talking about Jewish people, or a Jewish influence, in generalities immediately suspect. The fact remains, though, that Jews in America represent a very important economic and voting bloc. To a lesser extent Fundamentalist Christians who feel a commitment to Israel (even though some of the ones I’ve dealt with seemed at the same time to be anti-Semitic on a personal level) also wield such an influence, particularly in certain specific Congressional districts.
This helps account for why the U.S. has, far and away, used its veto power more often than any other permanent member of the U.N. Security Council; time and again the U.S. has blocked resolutions critical of Israel which were supported by nations which otherwise largely share a common world view with the U.S.–Canada, Great Britain, etc. There have also been many, many instances in which a resolution has passed the U.N. General Assembly with just two dissenting votes–the U.S. and Israel.
This also accounts for why the largest recipient of U.S. foreign aid in recent decades, far and away, has been Israel. The second largest year after year has been Egypt; the U.S. directs aid there as a way of maintaining stability and enhancing Israel’s stability.
Another factor is that the Islamic nations in the region have, on the whole, been so inept in pressing their case during the years. In 1967 a coalition of them launched a sneak attack on Israel, and were defeated in a humiliating rout in just six days. Ever since Israel has occupied and exploited terrritory it seized in that war in defiance of U.N. declarations, and the U.S., committed to suporting Israel generally, has been put in the position of steeling its position and siding with Israel more and more exclusively.
As for the role of the mass media, one can argue endlessly, and fruitlessly, about its supposed liberal or conservative bias. The fact remains, though, that as Vincent Bugliosi once observed, its motto often seems to be “I came, I saw, I concurred”; major media outlets in this country have a way of finding and adopting a simplistic consensus, identifying good guys and bad guys, and sticking to those identifications in favor of more complex or nuanced positions.
None of this requires a Jewish “conspiracy”, only a recognition that a strident and consistent lobby, particularly one with money to spend, can have a disproportionate influence on U.S. policy. The same can be said for Cuban expatriates, retirees, and numerous farm blocs, to name just a few parties with a powerful and consistent influence on U.S. policy which can result in one-sided and single-minded policies.