Bernie was a fan of the Soviets. Any republican candidate would be devoured by the media if they had vacationed in the Soviet Union much less if they had their Honeymoon there making some of the statements Bernie was caught making. To be fair to Demcorats though Bernie is NOT a Democrat even if he chooses to run in the election as a Democrat. That's the good news for the Democrats but the bad news is that there are many others within their party that are just as radical and socialist if not worse.
Bernie, I believe, missd his chance when he chose to attmept to run a civil campaign against Hillary in 2016 because Hillary was going to be ruthless in her campaign against anyone else and in fact the Democrats fixed the primaries with their super delegates to favor Hillary and totally exclude Bernie no matter how well he performed. With Biden entering the race I doubt that Bernie will continue to remain in second place.