Conan O’Brien returned to Harvard University on Thursday for a commencement address that mixed the absurd humor of his late-night career with a direct defense of international students and a call for renewed empathy, the Associated Press reported. The speech came as the school navigates an escalating conflict with the Trump administration, which has moved to restrict Harvard’s ability to enroll students from abroad.

O’Brien, who graduated in 1985 and served as president of the Harvard Lampoon, opened with a quip about the institution’s dual reputation. “Harvard has produced more Nobel laureates or white-collar criminals than any other university in the country,” he said, according to the AP. “So whether you choose good or evil, know that you are among the very best.”

The comedian later alluded to the political pressure on the university by suggesting that “Justice Department spies” might be in the audience—a joke that drew laughter but also reflected the real federal scrutiny the Ivy League school faces.

The core of the speech pivoted from comedy to a more somber message. O’Brien spoke out against what he called a broader decline of compassion in the United States and specifically criticized the Trump administration’s efforts to block Harvard from hosting international students. His remarks turned the commencement podium into a platform for a principle he argued should guide the new graduates: that empathy, not indifference, must anchor public life.

Graduates and faculty at the outdoor ceremony in Cambridge received the address warmly, the AP reported, as the university community confronts an unprecedented federal campaign against elite higher education.