COROAPOLIS, Pa. — “There is no limit to what we can achieve when we set free the dreams of our incredible people,” President Trump said to a crowd of supporters standing on a decidedly cold cement floor of an equipment company in suburban Pittsburgh.

He paused and told them they were incredible people, then peeled off a list of American achievements over the ages, from the early frontiersmen, to the workers who dug out the Panama Canal, to the building of the Empire State Building and the Hoover Dam, and the launching of a man onto the face of the moon.