Fox News senior judicial analyst Judge Andrew Napolitano told viewers Thursday on “Special Report with Bret Baier” that Pope Francis’ recent comments about Donald Trump illustrate he “likes to opine in areas outside his expertise.”

“A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian,” His Holiness said Thursday, responding to a reporter’s question about Republican frontrunner Trump’s promise to build a wall between the U.S. and Mexico.

Later, Trump responded, saying that “for a religious leader to question a person’s faith is disgraceful.”

“I say what I'm about to say as a practicing traditionalist Roman Catholic,” Napolitano said, “Before Vatican II [a landmark 1960s Vatican council meeting], you didn't have to say ‘traditionalist,’ now you do. The Pope likes to opine in areas outside his expertise; as far away from Catholicism as economics, the environment, and now American domestic politics. I think he should stay out of it.”

“I happen to disagree with Donald Trump on the wall. I disagree with Donald Trump on mass deportations. The pope's entitled to a political opinion, but when the pope gives a political opinion, there's this imprimatur, no pun intended, on what he says. He didn't become the pope to lead Catholics to vote for or against an American politician.”