US President Donald Trump ushered in the 250th anniversary of American independence on Saturday in South Dakota at Mount Rushmore talking about American exceptionalism, before veering into a darkly political speech with warnings about a sinister threat of communism that evoked one of the country’s ugliest chapters.

“Communism is a mortal threat to American liberty,” he says, “It is the greatest threat to our country, including World War I, World War II, Pearl Harbor or even 9/11.”