At one time, the presence of Catholics on both major-party tickets would have been cause for celebration. But now Mr. Vance and Mr. Biden reflect the political divisions among U.S. Catholics.

"Together with my brother bishops, we condemn political violence, and we offer our prayers for President Trump, and those who were killed or injured," said Archbishop Broglio, the president of the U.S. Conference of Catholic Bishops.

Many political and faith leaders, even as they prayed for Trump, also asked for prayers for the country as a whole, and particularly America’s polarized political landscape.

Trump’s campaign said the presumptive GOP nominee was doing “fine” after the shooting, which he said pierced the upper part of his right ear.

Too many people opposing Mr. Trump have adopted an us-vs.-them mentality. Democrats must attempt to bridge the real divisions in the United States.

Most adult Catholics in the United States say the church informs their opinions about immigration at least “somewhat,” but only 19 percent say it informs their opinions “very much.”