Massachusetts Senator Elizabeth Warren, the darling of the Democratic Party’s liberal wing, touted as a possible 2016 presidential candidate, told a Tufts University audience last week that she found it “fair” when a questioner compared Israel’s actions to those of Nazi Germany. The exchange distilled a question that is likely to be consequential both for Israel and for American liberalism: how much will liberals allow their stance toward Israel to be influenced by the Israel-hating radical Left?

When The Weekly Standard’s Daniel Halper broke the Tuft’s story last week, the liberal blog, TalkingPointsMemo, accused Halper of “distort[ing]” the Senator’s remarks and quoted her press spokesman’s claim that Halper had “grossly mischaracterized Senator Warren’s response.”

It is true that Warren had voted for aid to Israel during the Gaza war and had, at a Cape Cod forum a few weeks earlier, justified her vote by citing Israel’s “right to defend itself” even though Hamas “puts its rocket launchers next to hospitals, next to schools.” But Halper had neither distorted nor mischaracterized what the Senator said at Tufts. The most that could be argued in extenuation was that the phrasing of the question to which she responded left a slim margin for interpretation.

Identifying herself as a “Holocaust refugee,” an audience member said, “I’m extremely concerned that Jews don’t do to another people what was done to them.” To this, Warren replied, “I think that’s fair.” The questioner then added, “You’ve recently said that…Israel has a right to self-defense. Do you also believe the Palestinians have a right to self-defense?” To this Warren replied, “Of course. The answer is yes. The direction we need to be moving is not to more war…I believe in a two-state solution.”

Conceivably, defenders could argue that by her first reply Warren only meant to agree that Jews should not perpetrate a Holocaust rather than that they had done so already, and that by her second she meant only that the Palestinians had a theoretical right to self-defense not that Hamas’s rocket-fire amounted to self-defense. But these would be lawyerly constructions, begging the question why Warren had refrained from refuting head-on the Israel/Nazi parallel or the implication that Hamas was acting in “self-defense.” Indeed, offstage immediately after, a television reporter prompted the Senator to say anything at all pro-Israel, “So if people feel you are favoring Israel in any way, that is wrong?” But Warren refused this bait, replying simply: “I think that peace favors both peoples, and that’s what we really need.”

It is unlikely Senator Warren was caught off guard by the Tufts questioner. Warren’s previous affirmation of Israel’s right to self-defense had infuriated Massachusetts Peace Action, a leftist group that stationed protestors outside the meeting with a large banner saying: “Senator Warren: Stop Excusing Israeli War Crimes.”

The questioner inside the hall who posed the Israel/Nazi parallel was Eva Mosely, an officer of that group. And the entire encounter was written up by another officer on the hate-Israel website Mondoweiss. According to this account: “As she exited the auditorium, Warren…approached the activists, shook their hands and warmly thanked each of them for being there.”

Meanwhile a Warren aide told them “that the senator was taken by surprise at the Cape Cod meeting [the one at which she had defended Israel] and that she spoke ‘off message’ as a result.”

Clearly, the Senator was trying to tiptoe between the plurality of Democratic voters who remain pro-Israel and the activists of the Left who are quite the opposite. Due at least in part to the Left’s influence, liberal Democrats, who once were Israel’s most ardent backers, have become the political segment weakest in support for the Jewish state. A Pew poll in the first half of July found what it called the largest “partisan gap on Israel support…in 40 years.” Seventy-three percent of Republicans supported Israel, compared with 44 percent of Democrats. Broken down by ideology, “liberal Democrats” recorded only 39 percent support. A subsequent poll a few weeks later, asking “which side was more responsible for the current violence” found a similar divide, with liberal Democrats as likely to blame Israel for the Gaza fighting as Hamas. And 44 percent of them said Israel had “gone too far” in the war while only 33 percent said Israel’s reaction was “about right.” (In contrast among conservative Republicans 10 percent thought Israel had gone too far while 51 percent thought its actions about right.)

According to the Massachusetts Peace Action website, the outspoken Eva Mosely who confronted Warren at Tufts “cut her political teeth in Henry Wallace’s 1948 presidential campaign” which Wallace himself later ruefully acknowledged had been largely controlled by Communists. In that era American liberals like Hubert Humphrey and Arthur Schlesinger, Jr. found the courage to forthrightly denounce Communism. As a vehicle for this position they formed the flagship liberal organization, Americans for Democratic Action. Their stance proved beneficial both to America and to the cause of liberalism.

Communism has vanished as a polestar for the radical Left. Today, anti-Israelism has supplanted anti-capitalism as the signature issue of the Left. Will the current generation of liberals reject the Left’s pressures as those of Humphrey’s and Schlesinger’s day did? Senator Warren’s stumbles suggest that the answer is still up in the air.

Joshua Muravchik is the author of Making David Into Goliath: How the World Turned Against Israel. Click here to read an except about the radical left and its leverage over liberalism.