PROVIDENCE, R.I. — Anyone who doubts the gravity of the threat to Israel and Jewish students on American college campuses could have stopped by the Brown University campus here on Thursday night.

Students and community members attempting to listen to a conversation about Jewish identity between actor Michael Douglas and Soviet dissident turned Israeli political figure Natan Sharansky had their event intruded on by loud chants of “free, free, Palestine” from protesters outside.

Don’t blame Brown. The event was crawling with university and city police, along with Mr. Sharansky’s formidable security detail. The protesters have as much right to speak on campus as Mr. Sharansky, 68, and Mr. Douglas, 71, do. Though they do not necessarily have the right to speak so loudly and closely as to drown out the Jewish identity event, or to distribute inside the lecture hall, as they did, a slickly worded handout accusing Israel of “ethnic cleansing” and libeling Mr. Sharansky as “an infamous anti-African racist” while falsely representing the flier as a “program addition.”

The protesters failed to stop Mr. Sharansky from delivering his message, though the noise they generated outside could be heard inside the lecture hall for what seemed like a long while.

But it’s nonetheless a sad moment for American higher education, for Israel, and for world Jewry when a campus conversation between an American actor with a Jewish identity and a human rights hero known for surviving nine years in the Soviet gulag is greeted — before it even happens — by an op-ed in the student newspaper summoning a rally “to speak out against this justification of Israeli crimes.” It’s a measure of the movement’s virulence that it targeted not an appearance by an Israeli general or a foreign policy talk but rather a discussion about Jewish identity.

Mr. Sharansky spoke about the anti-Israel protesters and the boycott, divest, sanction movement they represent. “The moment you move to a logical debate, they have nothing to say….They are only shouting,” he said. “Behind it there is a desire to destroy Israel. It is not about human rights. The question is, how to destroy Israel. My fear is they are discouraging so many young Jews from being connected to their people and to the state of Israel.”

In his comments at the Brown event, Mr. Sharansky encouraged students to explore and claim their Jewish identity. “First of all, always remember from where you came,” he said. “If you want to make the world a better place…you have to be strongly connected to your roots and your identity. This is your source of power to change the world.”

Some student questioners pressed Mr. Sharansky about what they described as Israeli settlements and occupation, with Mr. Douglas describing the West Bank settlements as “the one issue that has alienated more of Israel’s friends than any other.” Other audience members and questioners were supportive.

Mr. Sharansky engaged on the substance. “I feel very strongly the fact that we are controlling the lives of other people is very bad for us,” he said. He recalled resigning from the government of Prime Minister Sharon when Sharon decided to withdraw unilaterally from Gaza. “I wrote then that the missiles from Gaza will reach us,” Mr. Sharansky said, recommending an alternative strategy: “the right way is to strengthen Palestinian civil society.”

“Who will gain if Israel will go back to the borders of ’67 and Hezbollah and ISIS will control the West Bank?” Mr. Sharansky asked. He said he wanted the Palestinians ‘”to be an independent state as soon as possible,” but said it needs to be done without creating a terrorist state.

On the settlement issue, Mr. Sharansky said the Jewish Agency for Israel, which he chairs, leaves it up to individual immigrants to make a personal decision. “It’s their choice…wherever they choose to live,” he said. “We don’t have a policy of supporting settlements, we don’t have a policy of fighting against the settlements.”

More and more immigrants will be in the position to make such a decision; Mr. Sharansky said half of the 300,000 Jews in France have already decided that their children should not live there. Last year, 31,000 Jews moved to Israel, up from 20,000 two years ago, Mr. Sharansky said. Eight thousand of the new immigrants came from France, and Mr. Sharansky said that number could double in the year ahead if Israel solves some problems. “I told the prime minister, this year we could have 15,000 or 20,000 Jews from France,” he said.

Mr. Douglas, the son of a Jewish father — the actor Kirk Douglas — and an Anglican mother, described how his own Jewish identity had been awakened by his son who wanted a bar mitzvah. He also spoke of his early career. “My father was a big movie star, and I questioned whether I could be the man that my father was,” Mr. Douglas said. “I suffered from stage fright. I used to get violently ill before I’d go on stage. It did not come easy.”

Mr. Sharansky asked Mr. Douglas to consider having his own adult bar mitzvah. Mr. Sharansky, denied one as a youth in the Soviet Union, finally had one at age 65. “All the sweets that they throw at you, my grandchildren collect,” he said. Mr. Sharansky noted that the Torah portion for his birthday and bar mitzvah describes the Exodus from Egypt, an appropriate passage for someone with his life story.

Mr. Douglas said he might give it a try at age 83, when some seniors do a second bar mitzvah.

It was a sweet moment, a reminder both of progress and of room for more. The Soviet Union that once denied Jewish youths the possibility of having bar mitzvahs has been defeated, in part because of the courage of Mr. Sharansky and those like him. Yet when Mr. Sharansky comes to an American college campus to encourage others to celebrate bar mitzvahs or to otherwise embrace their Jewish heritage, he is greeted with protesters aiming to drown out his remarks and destroy the Jewish state.

A dispatch in the Brown Daily Herald, which had a reporter outside with the protesters, reported that they numbered about 30 — far fewer than the hundreds gathered to hear Mr. Sharansky and Mr. Douglas — and that among their slogans was “From the river to the sea, Palestine will be free!” The Herald also reported that, “Throughout the demonstration, Ashley Ferranti, assistant dean of student support services, reminded students of the University’s guidelines for staging protests. She also offered to provide further support for students who had missed class to be involved in activism or who were upset by the evening’s events.” The student newspaper said the protesters were able to gain entry to the lobby of the Sharansky-Douglas lecture “because they had booked a room” in the building where it was held.

Said Mr. Sharansky: “When our enemies are shouting very loudly…we can’t shout like them. It is not our strength. But we are strong enough to be free inside.”