RENO, Nev. — President Trump reverted to his script as commander in chief here on Wednesday.

The morning after he delivered an aggrieved and impromptu defense of his comments on the violence in Charlottesville, Va., Mr. Trump spoke in a more measured tone to the national convention of the American Legion, telling its members that “we are not defined by the color of our skin,” and that the country will overcome its challenges by reaffirming its common values.

“We are here to hold you up as an example of strength, courage and resolve that our country will need to overcome the many challenges that we face,” the president said, speaking slowly and gravely as he read from a teleprompter. “We are here to draw inspiration from you as we seek to renew the bonds of loyalty that bind us together as one people and one nation.”

It was a day-and-night contrast to Mr. Trump’s performance Tuesday night in Phoenix, where he lurched from subject to subject and accused the news media of ignoring what he insisted had been his message of unity in the aftermath of Charlottesville.

But such contrasts have become a recurring motif of his presidency: Mr. Trump has toggled between Teleprompter Trump and Unplugged Trump every day since the deadly clashes in Virginia, leaving Washington and the rest of the nation with a chronic case of rhetorical whiplash.