The hiring of Simone Zimmerman to be Bernie Sanders’ new Jewish outreach director demonstrates everything that is inspiring about Sanders as a primary candidate and everything that is frightening about Sanders as a potential Democratic nominee.

A zealous activist against Israel’s occupation of Palestine, Zimmerman represents many social justice–minded young Jews whose views have been largely excluded from mainstream politics. As the Jewish Telegraphic Agency reports, during the 2014 Gaza War, she was part of a group of Jews who held regular vigils outside the Conference of Presidents of Major American Jewish Organizations, reading the names of people killed in the conflict.*

A former president of J Street U’s National Student Board, she was a leader in If Not Now, a Jewish group dedicated to ending the occupation. Her ideology is not particularly radical—unlike many of Israel’s fiercest critics, she appears to believe in a two-state solution rather than a single bi-national state. But she is frank about Israel’s failings in a way that even left-wing Democrats—including Bernie Sanders—almost never are. As she tweeted last month when Israel appointed the settler leader Dani Dayan to be consul general in New York, “Am Jews shld see that Israel scorns liberal values, peace, 2states.”

By hiring Zimmerman, Sanders is once again connecting with a strain of millennial politics that otherwise has little representation. Just as millennials have rejected the pro-capitalist consensus of their elders—polls show them to be the only generation to prefer socialism—they also reject reflexive support of Israel. (In a Pew survey taken during the conflict in Gaza, adults between 18–29 were the only group to hold Israel more responsible for the fighting than Hamas.)

In February, after spending time on American college campuses, Israeli journalist Ari Shavit wrote about Zionism’s “millennial crisis.” “[T]he most pressing existential threat we face is the clash between Zionism and the zeitgeist of the 21st century,” wrote Shavit. “The fact is that while most young people in North America and Europe have adopted universal values, both Israel and the organized Jewish world are perceived as tribal.”

Yet if hiring Zimmerman taps into the zeitgeist, it also opens Sanders up to a fusillade of attacks. Like many young Jews who deplore the occupation, Zimmerman hates Israeli Prime Minister Benjamin Netanyahu. “Bibi Netanyahu is an arrogant, deceptive, cynical, manipulative asshole,” she wrote on her Facebook page last year, adding, “Fuck you, Bibi.” She has since edited the post, but the original is currently all over the right-wing media even though, at the moment, conservatives aren’t terribly interested in attacking Sanders, who is widely seen as a weaker general election candidate than Clinton. Were Sanders actually the nominee, Zimmerman’s hiring would spark a multiday festival of manufactured outrage.

If the electorate exclusively comprised millennials, this wouldn’t matter. But Israel, like capitalism, is actually really popular in America at large; in one 2015 Gallup poll, 62 percent of Americans said they sympathize more with Israel than with the Palestinians. Some of Sanders’ older Jewish supporters are already uneasy about his (mild) criticism of Israel. They’re particularly outraged by his mistaken claim in an interview with the Daily News that 10,000 Palestinians were killed in the 2014 Gaza conflict. (The number of deaths was actually 2,310.) “Sanders has been tone deaf on Gaza. And the interview with the Daily News was appalling,” the Jewish Telegraphic Agency quoted a 72-year-old supporter saying at a Jews for Bernie brunch in New York City. “He doesn’t go to the AIPAC conference, but he’s going to the Vatican? I mean, come on!”

If the Sanders campaign is about broadening the space for progressive ideas in American politics, hiring a leader like Zimmerman is a great idea. If it is about winning elections, it is risky, especially in a state like New York, where, running for Senate in 2000, Hillary Clinton had to answer, over and over and over again, for a pro-forma kiss on the cheek that she once gave to Suha Arafat, Yasir Arafat’s wife. Right now Sanders, the first Jewish candidate to win a presidential primary, trails Clinton among Jewish Democrats in New York; several polls show him down by double digits. If he wants to win more Jewish support, he’s unlikely to do it by doubling down on criticism of Israel, however valid that criticism is.

I understand that part of what Sanders supporters love about him is his unvarnished leftism, his refusal to poll-test his convictions. No doubt Clinton goes too far in the other direction. But her caution is born of hard experience—like weathering the idiotic uproar over Arafat. Perhaps she overestimates the power of the right-wing noise machine. Or maybe Sanders underestimates it.

One thing that separates progressives who are backing Sanders from those who are, however reluctantly, voting for Clinton is their view of the electorate. Sanders people tend to believe that on some level most Americans agree with them, even if they don’t know it yet. Sanders himself recently argued that if the corporate media were honest about the Republican Party’s terrible agenda, it would wither away to a tiny fringe, garnering no more than 10 percent of the vote. He cannot quite conceive of sincere ideological disagreement, of people rejecting his beliefs for reasons besides ignorance or corruption. Progressive Clintonites are much less likely to believe that a majority of Americans share their worldview. That makes their approach to politics more cautious and cynical. There is a gap between what they believe to be true and what they believe to be politically palatable.

The question, to me, is not whether it’s OK as a matter of principle to called Netanyahu an asshole—he most assuredly is. It’s whether a Democratic candidate for president can afford to be associated with that sentiment. Whatever your views about god and Zionism, to answer yes is to take a leap of faith.

Correction, April 14, 2016: An earlier version of this article misstated that a story about Simone Zimmerman was written by the Times of Israel. It appeared in the Times of Israel but was written by the Jewish Telegraphic Agency. (Return.)

Read more Slate coverage of the Democratic primary.