CHICAGO (AP) — Former FBI Director James Comey told law students in Chicago that the United States isn’t facing a constitutional crisis despite sharp divisions over the Trump administration.

Comey spoke to 300 students at the University of Chicago Law School on Tuesday, saying that the country “is being stress tested” under President Donald Trump but that the U.S. Constitution is working.

Comey argued the nation had been “more screwed up” in the past, including 100 years ago when he noted that millions of Americans claimed membership in the racist Ku Klux Klan.

Comey peppered his hour-long talk with references to Trump, once calling him “deeply insecure.” But Comey steered clear of certain sensitive topics, including impeachment proceedings against Trump.

Trump fired Comey as FBI director in 2017.