Trump Confronts Violence—and a Bitter National Divide

President condemns racism, bigotry and white supremacy after mass shootings, but critics want action on gun control

For any president, a crisis also represents an opportunity, and so it was for President Trump on Monday. The crisis came in the form of two horrific acts of domestic terrorism over the weekend. The opportunity was to use the moment to start changing the dangerously angry tenor of the national conversation.

That is what Mr. Trump attempted to do—or at least implied he wanted to do—when he spoke to the nation in...