President Trump’s recent jab at Bernie Sanders, calling him “a communist,” was meant as an insult. But the 2020 Democratic front-runner and Vermont senator might not have taken it that way.

In 1972, Sanders, then a gubernatorial protest candidate for the socialist Liberty Union Party, visited an alternative high school in Rutland, Vermont, to give his campaign pitch. During a question-and-answer session, Sanders, then 31, brushed off accusations of being a left-wing radical.