While commemorating the 250th anniversary of the US over the weekend, President Donald Trump made a speech that echoed a bygone era.

“Communism is a mortal threat to American liberty,” he said at a July 3 semiquincentennial event at Mount Rushmore. “It is the greatest threat to our country, including World War I, World War II, Pearl Harbor or even 9/11.”

It was one of 14 “communism” or “communist” mentions in a speech spanning 30 minutes. The next day, at a Fourth of July celebration on the National Mall, the president again devoted considerable time to warning about the specter of “communism,” vowing before a crowd of cheering supporters that “America will never be a communist country.”

Calling his opponents “communists” is shaping up to be Trump’s go-to rhetorical counterattack in the midterm election campaign. As democratic socialist victories in some Democratic congressional and municipal primaries have energized parts of the left — and worried more moderate party leaders — the president and his Republican allies are turning to the age-old tactic of “red-baiting.”

“This is not your granddaddy’s Democrat Party,” White House press secretary Karoline Leavitt said in a recent Fox News appearance. “These are communists.”