Don't Turn Israel Into Major US Election Theme

Alan Dershowitz wisely advises:

It is imperative that this election not be turned into a referendum over Israel's security in which a vote for the Republican candidate is seen as a vote in favor of Israel's security, while a vote for the Democratic candidate is seen as a vote against Israel's security. Such a perception could prove disastrous for Israel since it is very possible—indeed in my view likely—that President Obama will be reelected, and that his reelection will not turn on differences between him and Romney over Israel's security. That is why I am so concerned about the approach taken by those who argue that every Jew who supports Israel must vote for Mitt Romney, because President Obama's record on Israel is far from perfect.

My reading of this - if you force Americans to perceive the election as a referendum of US support for Israel - and the democrats won - will they not come to the conclusion that the American public does not support Israel as much as it is commonly perceived to?