So Sanders’ supporters are wrong to try to wave this attack away as a dumb distraction. (If this is irrelevant, then I never want to hear about Hillary Clinton having been a Goldwater Girl in 1964 ever again.) Because as a campaign tactic, it could have some salience in a general election. Not to convert undecided voters necessarily, though the number of moderates who barely pay attention to politics and could be swayed by such a sound bite is probably a lot higher than many partisans realize. But it could easily be used as a cheap scare to motivate conservative voters to get to the polls. Which is why Sanders and his team need to have sharp defenses at the ready.

Red-baiting of this type has never left our politics. We’ve seen it as recently as the last two campaigns, when conservatives tried to tie left-wing activists Bill Ayers and Bernardine Dohrn to Barack Obama. There were dark hints that the president was under the pernicious spell of the radical ideology these two former members of the Weather Underground had espoused in the 1960s. Even today, conservatives will still go out of their way to warn that Obama has turned the United States into a socialist nation.

The red-baiting of Obama was transparently silly to anyone who paid even the slightest attention to his politics and his governing style. But that undercurrent of fear of a leftist takeover is still present in the American psyche. So take a candidate who self-identifies as a democratic socialist (yes it’s different than a flat-out socialist, but good luck betting that the average American voter will recognize the subtle difference) and has based his campaign on calls for “revolution,” and you can see how, as Charlie Pierce put it over at Esquire, his statements on the Sandinistas “are fertile ground for conservative ratfcking.”

Seriously, watch that clip again. Sanders totally yadda-yaddas the less-than-admirable aspects of the Castro regime – the brutal repression and state-sanctioned violence against dissenters – by saying “Not to say that Fidel Castro or Cuba are perfect. They are certainly not.” Any Republican candidate who doesn’t put that into an attack ad so they can point to it and scream all sorts of slurs would be committing political malpractice.

So while this line of attack might be stupendously dumb, so are political campaigns. And bringing up New York Mayor Bill de Blasio as an example of someone who survived the Sandinista-supporter smear (yes, I have seen that argument made) is not going to cut it.