Rabbi Shmuley Boteach, a former close friend of Sen. Cory Booker (D-NJ), said in a statement Monday that Sen. Cory Booker (D-NJ) had suffered a decline in his political fortunes because he sided with the “Ilhan Omar wing” of his party.

Boteach, who has known Booker for nearly 30 years, was once a close ally of the New Jersey Democrat. As he explained in his statement: “Cory served as my student president at the Oxford University L’Chaim Society, a Jewish organization I founded, with thousands of Jewish and non-Jewish members, from 1992-1994. This began a 25-year soul-friendship of two men from distinctly different backgrounds, ethnicities, and religions, who became brothers.”

But Booker’s support for President Barack Obama’s nuclear deal with Iran created a split between the two — and with Booker’s Jewish constituents.

As Boteach wrote in a column at Breitbart News in 2018 titled, “What Happened to You, Cory Booker?”,Booker begun to embrace harsh criticisms of Israel, posing with a sign that said, “From Palestine to Mexico, all the walls have got to go.”

At the time, Boteach speculated that Booker was trying to appeal to the party’s left-wing activists by showing he could criticize Israel just as well as Sens. Bernie Sanders (I-VT) or Elizabeth Warren (D-MA). He went further on Monday: ” As some in the Extreme Left of the Democratic Party began to demonize Israel, Cory took the bad advice of his senior advisors that catering to the Ilhan Omar wing of the party and abandoning Israel would win over these extreme constituents and the perception of Cory’s inauthenticity continued to grow.”

Boteach added that Booker also flip-flopped on a variety of other issues: “This continued with his repudiation of school choice and other central tenets of his political ideology that made him so unique and electrifying in the first instance. And the more he changed his politics, the more the public perceived him synthetic and inauthentic.”

Booker blamed the difficulty of fundraising, and the scheduling conflicts posed by President Donald Trump’s looming impeachment trial, in explaining his decision to withdraw on Monday. He had also previously criticized the Democratic National Committee for debate criteria that created an all-white debate stage.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He earned an A.B. in Social Studies and Environmental Science and Public Policy from Harvard College, and a J.D. from Harvard Law School. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.