It is undeniable that a substantial faction of the Democratic Party is hostile to Israel. While it is important to distinguish between that faction and the Democratic Party writ large, the growth of that faction is still menacing and that faction exerts far more influence over other Democrats, including those who are generally supportive of Israel, than should be accepted. The question is what to do in response to the growth about that faction. One response is to register displeasure with the entire Democratic Party by voting Republican.
I find voting for today's Republican Party to be totally unacceptable. This is even more the case with the current leadership of the Republican Party, even with the consolation of reduced pressure over the settlements and pressure being placed on Iran. Despite what some might say, this is not an expression of blind obeisance to the Democratic Party. Indeed, if the Democrats nominate either Bernie Sanders or Elizabeth Warren, I will not vote for that ticket. However, like Bret Stephens, that would not lead me to vote for Donald Trump and I would instead vote for some third-party alternative of write someone in. In other words, there is a line that the Democratic Party could cross that would induce me not to vote for it, but not to affirmatively vote for the current Republican Party.
That is to say, I will not vote for the Republican Party as it is today. That does not that there is no way that I could vote for a Republican Party. If the Niskanen Center were to take over the Republican Party, I would happily vote for that Republican Party over much of the Democratic Party, including those who are not overtly anti-Israel. One of the features of the Niskanen Center is illustrated in Niskanen Center president Jerry Taylor's essay on post-ideology:
Over and over again, [we] engaged in fierce, uncompromising debate about empirical matters that had nothing to do with  principles or commitments. Is the Keynesian multiplier consequential? Is Thomas Piketty correct that returns to capital are greater than the rate of growth? Do tax cuts pay for themselves? [One] could take either side of those disputes without having to recant any of their principles or fundamental beliefs.What this snippet demonstrates is that according to Taylor, more important than having any specific position on any particular topic is remaining permeable to evidence. On specific policy issues, there are many cases in which the Niskanen Center pulls back from the line which causes me to reject movement conservatism, and those who genuflect to it. However, the simple willingness to submit ideological priors to testing, when feasible, based on observable effects in the real world is what makes productive debate possible. The Democrats have certain issues where they subordinate empirical evaluation to ideology, such as assessing what the Palestinian Authority and the Iranian theocracy want. The are other issues where both parties share ideological blinders, such as evaluating China's intents. However, the conservative movement, which controls the Republican Party outside of a handful of pockets, has more such issues where ideology trumps empirical reasoning. A change in that will lead me to change how I view the Republican Party.