As a UC professor, privy to a front-row seat, I know firsthand that being a Jewish student is not what it was like a mere five or 10 years ago. Anti-Semitism on campus is rising at an alarming and frightening rate. And it largely involves Israel.

Anti-Israel activists single out, harass, intimidate and even assault Jewish students, regardless of how that student feels about Israel. The vast majority of these students did not come to UC to defend Israel. They came to get an education, to make friends, to have fun. Yet, whether you support Israel or not, you are assumed guilty by association.

Modern-day anti-Semitism is not just about swastikas. When UC students from different campuses report fear of wearing a Star of David necklace because they might get spit on or yelled at by anti-Israel activists, and when a UCLA student reports she was afraid to walk to Hillel for sabbath dinner and another says she stopped telling people she was Jewish, that is anti-Semitism. When a UC Irvine student is stopped at a Palestinian checkpoint demonstration simply because she is Jewish, when members of a Jewish fraternity at UC Davis speak against divestment and their house gets spray-painted with swastikas, and when fliers are posted across UC Santa Barbara blaming Israel and Jews for 9/11, that is anti-Semitism.

UC San Diego has seen its fair share. After a virulent anti-Israel divestment campaign a few years ago, a UC San Diego student reported, “Jewish students feel targeted, and Jewish students don’t feel as safe or comfortable on campus.” Students were so frightened, one student, concerned that other Jewish students might be assaulted, cautioned them from walking alone.

What’s happening on too many UC campuses is frightening and only getting worse. The first step to fixing this is for students and faculty to understand what is welcomed debate and what is anti-Semitism. We need a schoolwide standard, a universal tool, for understanding anti-Semitism and identifying when it happens.

Our government has a definition used internationally to identify anti-Semitism. Unlike Webster’s general definition, the State Department’s definition is based on decades of research and it includes a thorough description of how modern day anti-Semitism manifests itself. It understands that comparing Israel supporters to Nazis and calling for Israel’s destruction is anti-Semitism. Pope Francis and President Obama agree. Both have stated that denying Israel’s right to exist is unquestionably anti-Semitism.

Opponents claim the State Department definition is overreaching. They argue it suppresses free speech and conflates criticism of Israel with anti-Semitism. They are flat-out wrong.

The State Department definition does not consider criticism of Israel similar to that leveled against any other country as anti-Semitic. Israelis don’t either. Nowhere is there a more robust critique about Israeli policies than in Israel itself. But debate and criticism are very different from a denial of Israel’s right to exist. That is anti-Semitism.

Adoption of a definition will not restrict speech. Its sole purpose is to identify anti-Semitism and allow UC administrators to use it in anti-discrimination education and to address anti-Semitism as they do all other bigotries.

If opponents want to speak of curtailing free speech, I’ve personally experienced fierce attacks on campus when expressing pro-Israel views. False reports accusing pro-Israel faculty of attacking “students of color” were widely issued by anti-Israel students, and happily echoed on the San Diego Faculty Association website. When a formal university investigation found these to be blatant lies, nothing could be done, since unlike “students of color,” Jews do not enjoy similar protection. And the goal was clear: to intimidate and silence Jewish voices.

Pro-Palestinian students and faculty should be able to speak out. Scholarly criticism and debate on Israel is welcomed. Pro-Israel students and faculty should be able to support Israel without retaliation. Debate is critical. It’s integral to the learning process. We must protect academic freedom and freedom of speech. But what’s happening on campus in the guise of anti-Israel debate has undeniably gone too far. It is jeopardizing the safety of students.

UC should adopt the State Department definition of anti-Semitism. It properly recognizes when scholarly criticism ends and anti-Semitism begins.

Dubnov is a professor at UC San Diego.