Regarding Israel, the history of that choice goes back to at least 1943:

https://en.wikipedia.org/wiki/Harry_S._Truman#Recognition_of...

In general, pro-Israel political groups understand this dog->tail relationship extremely well, have excellent political skills, and have been pouring resources into maintaining that status quo since WWII.

Vs. those who don't like the consequences of that dog->tail relationship are sadly unable or unwilling to play the political game at that level.

OR: Find somebody who's been around American political campaigns for the past half-century or so. Then ask him how 99% of Election Days work out, for candidates who are perceived as "insufficiently pro-Israel".