Bernie Sanders campaigned for Marxist party in Reagan era
Bernie Sanders campaigned for the Socialist Workers Party in the 1980 and 1984 presidential campaigns and was investigated by the FBI for his ties to the Marxist group.
Sanders has always played down the extent of his involvement with the party, which included radicals who praised the Soviet Union and Cuban communists, and has denied ever being a member. Asked in 1988 about his role as an SWP elector in 1980, he said: "I was asked to put my name on the ballot and I did, that’s true." In fact, his ties to the party are deep and enduring.
In 1980, Sanders "proudly endorsed and supported" Andrew Pulley, the party's presidential candidate, who once said that American soldiers should "take up their guns and shoot their officers." Sanders was one of three electors for Pulley on the Vermont ballot, stating in a press release: "I fully support the SWP's continued defense of the Cuban revolution."
Four years later, he backed and campaigned for the SWP presidential nominee Mel Mason, a former Black Panther, saying it was important for there to be "fundamental alternatives to capitalist ideology." During the campaign, Mason praised the Russian and Chinese revolutions and said: "The greatest example of a socialist government is Cuba, and Nicaragua is right behind, but it's still developing."
https://www.washingtonexaminer.com/news/campaigns/bernie-sanders-campaigned-for-marxist-party-in-reagan-era