In a wide-ranging interview, the historian Jonathan Sarna discusses American Jews’ relationship with Israel, the changing role of the major denominations, the recent presidential election, and whether U.S. Jewry will maintain its long-standing alliance with the Democratic party. (Interview by Dror Eydar.)

The truth is that anyone who studies Jewish history knows that the extremes on both sides are dangerous for Jews. Very often, there is a convergence of the extreme left and extreme right. My concern is that this election has given certain fodder to the extremes. Hillary Clinton was trying to find a more centrist path. The failure of that path has led some elements in her party to say that this was a big mistake, and that they should have run a campaign aimed at the Bernie Sanders wing of the Democratic party, which would have focused on real change, and would have succeeded, in their opinion. I am not sure that is true. Those people, whether you are talking about Sanders or Senator Elizabeth Warren or Representative Keith Ellison, are very [hostile] toward Israel, although some of their domestic proposals find favor in the eyes of many American Jews.

It will be very interesting to see four years from now which wing of the Democratic party wins. I would not be surprised if the somewhat anti-Israel left-wing rises. Then it would be very interesting to see which Jews say they absolutely cannot vote for its candidates and which Jews say, “I am an American citizen and I better agree with the domestic policies of these candidates. Nor am I fond of Israel’s policies.”

I expect that Jews would tend in both directions. I would be very surprised if in the 21st century the Jewish community is as strongly Democratic as it has been for the 80 years or so since Al Smith, [the Democratic nominee who lost the 1928 elections to Herbert Hoover]. My guess is that in the years ahead, we will see a voting pattern among Jews similar to that of the 19th century, when everybody understood that the Jews were divided politically and that they were also willing to shift back and forth depending on the candidate.

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.