In my life time the Korean War, the Cold War, Vietnam, the Iranian hostage crisis, Saddam's invasion of Kuwait, and 9-11 have all had decisive impacts on USA elections.
As to Jewish voting, the “NeoConservative” movement of the 1970’s was dominated by liberal Jewish intellectuals who rejected the pacifism and the Cold War appeasement of the Democratic Party.
Finally, except for Pat Buchanan, I can't think of any Conservative leader who is not assertively pro-Israel.
Philosophically, American Conservatism and vigorous support for Israel are inseparable.
Philosophically, the American Left and vigorous support for Palestinians are inseparable.
I can't imagine I will ever have to make a political choice between one side or the other.
Maybe not so much for conservatives. But consider Jewish liberals. They support a pro-homosexual agenda, are pro-abortion, and pro-large government.
And the only party in America that gives them that sort of agenda is the Democrap party. While it's true that they want to support Israel, they have to choose between a party that gives them the domestic policies they want and the foreign policy they hate, or a party that gives them the foreign policy they like and the domestic policy they hate.
Lieberman is a very good example of this. He was a Democrat, but could no longer stomach their foreign policies and so went Independent.
And for the rest, they are more willing to compromise on foreign policy than domestic policy, so they continue to vote Democrap. Kinda like the "Out of sight, out of mind" idea.