Sullivan & Cromwell, a 145-year-old firm that has counted Goldman Sachs and Amazon among its clients, says that, for job applicants, participation in a protest — on campus or off — could be a disqualifying factor.

The firm is scrutinizing students’ behavior with the help of a background check company, looking at their involvement with pro-Palestinian student groups, scouring social media and reviewing news reports and footage from protests.

It is looking for explicit instances of antisemitism as well as statements and slogans it has deemed to be “triggering” to Jews, said Joseph C. Shenker, a leader of Sullivan & Cromwell.

Sullivan & Cromwell’s policy stands out because of the way it holds applicants accountable for the actions of others, and considers commonly used protest slogans to be out of bounds. No other law firm on Wall Street has publicly discussed a similar policy toward protesters, but leaders at four of Sullivan & Cromwell’s elite rivals privately said they are considering adopting similar rules.

Candidates could face scrutiny even if they weren’t using problematic language but were involved with a protest where others did.

Soon after Oct. 7, he wrote a letter, signed by around 200 other firms, calling on law school deans to impel campus protesters to act civilly and to do more to protect Jewish students. If the schools had done so, Mr. Shenker said, his firm’s new policy wouldn’t be necessary.

But to Kenneth S. Stern, the director of the Bard Center for the Study of Hate, who studies antisemitism, the policy’s failing is that it doesn’t separate unpopular opinions from hateful speech. Mr. Stern, who said he believes in the importance of Israel as a Jewish homeland, thinks rules like this one will exclude candidates who would be valuable to the law firm.
“I’m offended by some of the chants, but that’s it — I’m offended,” he said.