MILWAUKEE — Four years ago, Shabbos Kestenbaum, a recent Harvard graduate who is suing the university over its handling of campus antisemitism, was a self-described progressive Democrat who voted for Rep. Jamaal Bowman (D-NY) and backed Sen. Bernie Sanders (I-VT) for president.

Now, the 25-year-old is poised to take the stage tonight at the Republican National Convention here in Milwaukee, where he will recount the experiences of Jewish students at Harvard amid a sharp rise in antisemitic activity sparked by Hamas’ Oct. 7 attack on Israel and its war in Gaza, among other issues.

It’s a striking evolution for Kestenbaum, an Orthodox Jew from the Bronx neighborhood of Riverdale who graduated from Harvard Divinity School in May and has been outspoken in recent months against his alma mater as well as what he has criticized as his own party’s failure to counter antisemitism and maintain strong support for Israel.

But the decision to accept an invitation to speak at the RNC, he insisted, is more a reflection of what he has described as his alienation from a party he once viewed as a political home — rather than an explicit endorsement of former President Donald Trump’s GOP.

“As Ronald Reagan said, ‘I didn’t abandon the Democratic Party — the Democratic Party abandoned me,’” Kestenbaum told Jewish Insider on Wednesday in an interview outside the Fiserv Forum, the main convention hall, hours before his speech.

Kestenbaum explained that he still believes in “progressive policy,” referencing his support for a $15 minimum wage and universal health care. “But Israel’s a progressive issue,” he said. “It’s a bastion of liberalism in an unstable region, and I cannot understand why my party — the one I registered to vote with the day I turned 18 — has turned its back on this important ally.”

“Unfortunately, electoral politics is binary — one person will win and one person will lose,” he added. “But there should be some nuance, and there should be recognition from Republicans and Democrats alike that we need to work together to instill basic common-sense policies. Combating antisemitism is one of them.”

Kestenbaum declined to confirm which party he would support in November, even as the Trump campaign said in announcing his speech last week that he “will be voting for” the former president “for the first time this year.”

Instead, he told JI, “I will be supporting Donald Trump’s policies to tax university endowments, to expel students who violate our foreign visa policies and to instill patriotism in our school systems yet again,” using language from the newly approved GOP platform. 

He also voiced approval of Trump’s handling of anti-Jewish discrimination while in office, saying his federal lawsuit against Harvard — filed with five other Jewish students — had been made possible thanks to the former president’s executive order calling on government departments enforcing Title VI of the Civil Rights Act of 1964 to adopt the International Holocaust Remembrance Alliance’s working definition of antisemitism.

“It’s because of his classification of Title VI that we’re able to proceed,” Kestenbaum said, noting that he next will be in court on July 24 for a hearing to address Harvard’s motion to dismiss the case.

During his time in Milwaukee, Kestenbaum said he has felt a “very strong connection with Jews and non-Jews alike, good, everyday Americans who’ve come up to me in the last day and a half I’ve been here and said, ‘We stand with the Jewish people — we’re praying for you guys.’ That’s incredible.”

“There was a remark last night that if someone were to mention the State of Israel at the RNC, there would be an applause,” he recalled of a speech by Matt Brooks, the CEO of the Republican Jewish Coalition. “If you mentioned the State of Israel at the DNC, there would probably be heckles and boos. That’s a very damning indictment on the state of my party.”

But even as he spoke positively of his experience at the convention, Kestenbaum — among a handful of current and former Jewish students addressing the crowd this week — expressed strong reservations about the GOP’s decision to give prominent placement to several speakers who have espoused antisemitic rhetoric, including Rep. Marjorie Taylor Greene (R-GA) and Tucker Carlson.

“I think it’s important to have a big tent, but not a tent so big whereby it includes bigots, antisemites and those who sow division,” he said, arguing that Greene and Carlson, among others, “represent the worst aspects of our politics. They should have no place in the Republican Party, and they should have no place at the Republican Convention.”

For his part, Kestenbaum said he has faced severe criticism in recent days over his upcoming speech, including from within the Jewish community. “It’s very difficult,” he said. “I think people are assuming my politics. They’re saying things that I never said.”

His response: “If they want to criticize, fine,” he told JI. “But more importantly, join me in the fight to combat antisemitism on our college campuses.”