“I don’t believe guns belong on campus,” he said in an interview in his office minutes after returning from a meeting at the Capitol, just four blocks from campus. “We had more than 3,000 comments on this from students and faculty, and they overwhelmingly opposed it.”

The law allows private colleges to ban concealed weapons, and nearly all of them have done so. Faculty at the University of Texas pushed hard to allow professors to do the same with their classrooms, but Mr. Fenves pushed back, because he thought the law would not permit it.

“I wish, like private colleges, we could prohibit guns,” he said. “We don’t have that option.”

The Austin campus has imposed a warren of exclusion zones to protect students and sensitive areas, but Mr. Fenves has tried to limit signs marking those zones. He told his campus safety team that he did not want the campus to “look like a war zone.”

The best outcome, he said, would be that the law had no noticeable effect and that a year from now the campus had forgotten about it. He worries, though, that it will affect recruiting.

“Already we’ve lost a dean over the issue,” he said. “We are concerned about it, and we will continue to monitor it.”