Most American Jews do not base their vote on Israel. They base their vote on what they think is best for America. Often those two things intersect in the Democratic candidate. Regarding the current President, Pres. Obama, he will receive close to 80% of the American Jewish votes because the Republicans are nightmares who, among many other flaws, don't understand how science informs and functions in a modern society. That alone is enough to drive Jews to the Democratic candidate.
Key U.S. House Democrat cites troublesome issues in Iran nuclear deal (Reuters)