On June 8, British voters will head to the polls, three years early. When Prime Minister Theresa May called last month for a snap election, the assumption was that she would win easily and increase her parliamentary majority. Recent numbers, however, show the gap closing between May and Labour leader Jeremy Corbyn.

Corbyn — who was given 200:1 odds of when he ran for the party leadership in 2015 — is doing surprisingly well again. This is despite the fact that Labour has been under fire for anti-Semitism in its ranks, and Corbyn himself has been accused of anti-Jewish bigotry. Corbyn denies having a problem with Jews, claiming that he is merely anti-Israel. Even if it were possible to hate Israel without being anti-Semitic — and I am not sure that it is — Corbyn's words and deeds demonstrate that he often uses virulent anti-Zionism as a cover for his soft anti-Semitism.

For example, in a speech last year, he said that Jews are "no more responsible" for the actions of Israel than Muslims are for those of the Islamic State. In 2009, he announced: "It will be my pleasure and my honour to host an event in Parliament where our friends from Hezbollah will be speaking. I also invited friends from Hamas to come and speak as well."

The company that Corbyn keeps, too, suggests that at best he gives a free pass to bigotry, racism and anti-Semitism within the ranks of his own party, and at worst, he espouses them. He has shared speaking platforms and led rallies with some of the most infamous Jew-haters. He has attended meetings hosted by Sept. 11 conspiracy theorist Paul Eisen, author of a blog titled, "My Life as a Holocaust Denier." He has been associated with Sheikh Raed Salah — leader of the outlawed northern branch of the Islamic Movement in Israel, a blood libel perpetuator convicted for incitement to violence and racism — whom he referred to as a "very honoured citizen" whose "voice must be heard." Corbyn was also a paid contributor for Press TV, Iran's tightly-controlled media apparatus, whose production is directly overseen by anti-Semitic Supreme Leader Ali Khamenei.

One of the biggest criticisms of the "Corbynization" of British politics has been the mainstreaming of traditional anti-Semitism. The country's chief rabbi, Ephraim Mirvis, has called the problem within the Labour Party "severe."

Consider the late Gerald Kaufman, a Labour veteran and close political associate of Corbyn's who touted conspiracy theories about Jews throughout his political career. When speaking at a pro-Palestinian event, Kaufman said: "Jewish money, Jewish donations to the Conservative Party — as in the general election in May — support from the Jewish Chronicle, all of those things, bias the Conservatives." While Corbyn condemned this remark, he refused to yield to widespread demands for disciplinary action against Kaufman. This is in keeping with what a key former adviser to Corbyn, Harry Fletcher, wrote: "I'd suggest to [Corbyn] about how he might build bridges with the Jewish community and none of it ever happened."

Let's be clear: I do not believe that Corbyn's rise in the polls is due to his hatred of Jews and Israel, but rather in spite of it. May called for elections and then refused to debate her opponents. She is running a lackluster campaign somewhat reminiscent of Democratic Party candidate Hillary Clinton's last year. For his part, Corbyn is a populist, like President Trump. Although politically polar opposites, they have much in common, such as a penchant for shooting from the hip and unpredictability.

Furthermore, many British voters are unaware of Corbyn's anti-Semitic associations. Others know but don't care. Those on the hard-Left, such as union activists and academics, include knee-jerk opponents of the nation-state of the Jewish people and supporters of academic and cultural boycotts of Israel. Many of these favor trade and engagement with such egregious human-rights violators as Iran, Cuba, China, Russia, Belarus and Venezuela. Singling out Israel — the Middle East's only democracy, with one of the world's best human-rights records, rule of law and concern for enemy civilians — for boycotts itself is a form of anti-Semitism.

Corbyn himself has called for boycotts of the Jewish state. He has advocated for an arms embargo, citing Israel's supposed "breach" of the human rights clause of the EU-Israel trade agreement. He also led the call to boycott Israel's national soccer team during a Euro 2016 qualifying match in Wales. (Ironically, Israel only plays in this confederation because it was expelled from the Asian Football Confederation due to the Arab League's boycott.)

Corbyn, as well, has been a vocal supporter of the so-called Palestinian "right of return," something that would lead to an Arab majority and Jewish minority within Israel, and render the two-state solution completely obsolete.

Whether anti-Semitism is the cause or effect of the Labour Party's problem is not important. What is relevant is that Corbyn not only has not stemmed the tide, but has played a big part in perpetuating it.

British voters now have the opportunity to choose where they will go as a nation. Will they opt to move away from stability, rationality and tolerance toward simple-mindedness and xenophobia? I sincerely hope not.

Sen. Bernie Sanders has already made his choice. He is campaigning for Corbyn despite his record on anti-Semitism. Sanders will have to explain why a Jew is helping to elect a bigot with the views Corbyn holds about the Jewish people and their nation state.

Alan Dershowitz (@AlanDersh) is the Felix Frankfurter Professor of Law, Emeritus, at Harvard Law School and author of "Taking the Stand: My Life in the Law" and "Electile Dysfunction: A Guide for the Unaroused Voter." This article was previously published by the Gatestone Institute.

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