In the 1970s, there was a lot of interest in “End Times” (a loose term referring to Christ’s Second Coming), probably because the 1960s had been such an uncertain time in the US (threat of nuclear war, the Cuban missile crisis, Vietnam, …). It spawned a literature and inspired songs, perhaps the most famous of which was Barry McGuire’s version of Eve of Destruction. American evangelicals looked for certainty and the wacky end thought it would be a good idea to hasten the world towards its end.
Of course, it was poor theology.
More recently, support for Israel has been based partly on the fact that the Christian Bible contains much Jewish writing. It is also another way for the American Right to distinguish itself from the Left, where the support is frequently for Islam, much like abortion was used as a wedge issue. (And, apart from the Netanyahu régime, Judaism is a more attractive and familiar cause than Islam.)