One of the outrageous aspects of campus politics — and, to a lesser extent, off-campus politics — is the effort by Israel’s detractors to tell Jews what constitutes antisemitism. This is remarkable, especially when you consider how women or gays or African Americans would react to people telling them that they don’t have the right to define sexism, homophobia or racism.

Equally shameful is the response of university officials and civil libertarians — who would never defend other forms of bigotry, but bend over backwards to suggest antisemitic attacks on Israel, and BDS advocacy, are acceptable forms of expression, or protected by academic freedom.

Germans do not have the same blinders. They know what antisemitism is, and what can follow from allowing it to go unchecked. It is, therefore, not surprising that opposition to BDS is so strong in Germany.

In February, for example, politicians from the Christian Democratic Union Party call BDS antisemitic. In August, Munich adopted anti-BDS legislation, and Frankfurt banned BDS activity. A month later, Berlin’s mayor vowed to block the use of city venues and funds by groups or event organizers that support BDS. Just this week, the Green Party in the southern German state of Bavaria passed a resolution rejecting BDS because it is “anti-Semitic, hostile to Israel, reactionary and anti-enlightenment.”

Students in Germany, unlike their peers in America, also have a clear understanding of BDS, which led Leipzig University to adopt an anti-BDS bill. For Germans, the boycott of Israel is distressingly familiar. As the student parliament at Goethe University in Frankfurt observed in this succinct and searing indictment of the movement:

The call by the BDS campaign to boycott products from the parts designated “occupied territories” of the West Bank, east Jerusalem and Golan Heights stands clearly in the tradition of the national socialist Jewish boycott and the slogan “Don’t buy from Jews!”

That’s right — Germans are calling BDS advocates Nazis. They’re saying that celebrities, professors, Students for Justice in Palestine, Jewish Voice for Peace, and other BDS proponents are like the stormtroopers that vandalized Jewish businesses and enforced a boycott against them — for the sole reason that they were owned by Jews.

True as the comparison may be, Jews could never get away with it. This is one instance, however, where Roger Waters and the rest of his ilk cannot blame the Jews for trying to silence them. Informed, intelligent, non-Jewish German students have called you out for what you are: antisemites.

The German students get it, but too many Americans do not. One explanation is political correctness. Students, particularly self-described progressives, do not like labels — except racist, sexist, homophobe, Islamophobe, etc. Many gullibly accept that Palestinian suffering is all the fault of the Jews, and can be ameliorated by punishing Israel. Students, professors and officials also swallow the sophistry of Israel’s detractors when these inheritors of Nazi ideology deny that their views are antisemitic.

American students are also famously ignorant of history. They have little or no knowledge of the Middle East, so it is easy for them to be bamboozled by emotional pleas and distorted, if not entirely fictional, narratives about the Palestinian-Israeli conflict. Germans, like most European students, are more knowledgeable about the world beyond their campus. They may not have any greater expertise on Middle East issues, but they do have a historical perspective.

Germans obviously have a unique reason to be cognizant of the dangers of promoting Jew-hatred. For most American students, the Holocaust is as relevant to their lives as the Peloponnesian War. For Germans, it may be part of their family history.

Germans also see the alarming rise in Europe of far-right political parties that espouse antisemitism. Americans, however, pay little or no attention to trends abroad, and are mostly unaware of the lunatic fringe in the United States, except when they crawl out from under their rocks, as they did in Charlottesville. On campus, however, the extremists promoting BDS are allowed to run loose, spewing anti-Israel venom and promoting an agenda that seeks the destruction of the homeland of the Jews.

The good news is that BDS is a marginal movement in the United States that has failed miserably. Like any purveyors of sleaze, however, they pollute the environment. They should not be allowed to turn the campuses into ideological toxic waste dumps.

American Jewish students need to take a cue from their German peers and stop being afraid to call the BDS advocates what they are — antisemites. It is also incumbent upon universities to treat them with the same derision and intolerance as they do other bigots.

Dr. Mitchell Bard is the author/editor of 24 books including the 2017 edition of “Myths and Facts: A Guide to the Arab-Israeli Conflict,” “The Arab Lobby,” and the novel “After Anatevka: Tevye in Palestine.”