In 2013, Thomas Tobin, the Catholic bishop of Providence, announced that he’d registered as a Republican. It caused a minor scandal, not because a bishop declared partisan loyalties, but because his loyalties weren’t to the Democratic Party, home of people such as New York's Gov. Al Smith and President John F. Kennedy. In politics, America’s Catholic prelates are Democrats almost to a man. They’ve denounced President Trump’s border wall with far more vigor than they ever demonstrated when it would have mattered during the same-sex marriage debate. They spent the entire lead-up to Obamacare trying to sweeten and woo Barack Obama, leaving nuns to fight his birth control mandate by themselves. Bishops are citizens and have the right to their views, just as you and I do. None of our shepherds will deny, however, that...