A year ago, when Timothy Snyder and his wife, Marci Shore, both prominent Yale historians, moved to Canada after being recruited to the University of Toronto, they thought it would be a fun adventure.

“I was trying to have a positive midlife crisis,” Professor Snyder said in an interview.

By the time they had settled into their new home, the mood in the progressive academic circles that feted them back in New Haven, Conn., was rapidly darkening after the election of Donald J. Trump in November.

The Trump administration has put U.S. colleges in its cross hairs, accusing some of cradling haters of America. It has launched policies that threaten to expel international students and jeopardize funding and academic freedoms.

Professors Snyder and Shore, along with Jason Stanley, a Yale philosophy professor who also moved to Toronto, have in recent months become outspoken about the Trump administration.

They published a widely shared New York Times video opinion piece titled, “We Study Fascism, and We’re Leaving the U.S.”

At the University of Toronto’s Munk School of Global Affairs and Public Policy, they joined Brian Rathbun and Nina Srinivasan Rathbun, international relations professors who made a similar move last year from the University of Southern California.