On Thursday afternoon, Senator Bernie Sanders voted against legislation to put new sanctions on both Russia and Iran. He voted for a Russia-only sanctions bill, but opposed the final bill’s inclusion of new sanctions on Iran because, like John Kerry, he feared it would endanger the 2015 nuclear deal.

I tweeted out a screengrab of Sanders’ statement saying as much, and noted that he was one of only two senators to vote no. Then I went about my business. When I checked Twitter an hour later, all hell had broken loose.

Sanders, according to a substantial number of Twitter users who replied to my original post, voted against the sanctions because he is an agent of Vladimir Putin.

I could go on, but you get the picture. I spend a lot of time online—too much time—and had literally never heard this insane theory before, and so the volume at which people were shouting it flabbergasted me. So did the fact that each and every person advancing it appeared to be a liberal; “Resist” avatars and usernames with “Covfefe” worked in were everywhere. How did this happen?

The jumping-off point seems to have been when Peter Daou, an avowed Hillary Clinton fan and major Twitter personality, quoted-tweeted my original post. Daou spends almost as much time energetically trashing Sanders as he does attacking Trump, and many of the respondents were followers of his. He certainly did not imply Sanders was a secret KGB asset, though, writing only: “Bernie Sanders and Rand Paul were the ONLY TWO VOTES **AGAINST** the Russia sanctions bill. Bernie was out of sync with every Dem senator.” (It was a Russia/Iran sanctions bill, and Sanders made it clear he objected only to the Iran part, but never mind.)

So how did people jump to this conclusion that Bernie Sanders, by opposing Democrats, must ipso facto be working at the behest of Russia? It wasn’t entirely organic. And it points to how fake news can infect some of our brethren on the left.

Blame starts with the people with megaphones that peddle this nonsense. Eric Garland, who became a Twitter celebrity with his bizarre “game theory” thread, has explicitly tied Sanders to Russia in his threads. So has Melissa McEwan on her Shakesville blog. “Bernie Sanders, who has visited Russia, has not been, to my knowledge, suspected of being vulnerable by Russian kompromat cultivated on his visits, unlike Donald Trump. But, as I said above, if I intend to say something, I will state it plainly, and here I am plainly stating that I do believe these connections warrant more scrutiny,” she wrote. The Palmer Report, which churns out Russia-related fake news by the pixel load, wrote a post in April: “Bernie Sanders must disclose what he knows about his campaign adviser Tad Devine and Russia.” And of course, uber-grifter Louise Mensch has joined the conspiracy theorists. 

Since most of the people replying to my tweet cited this Devine connection (he used to work with Paul Manafort), I assume these posts were the genesis. But it’s also possible people have also just been conditioned to believe that Russia is behind every single political action they find harmful.

People’s vulnerability to this sort of fake news is understandable, in a way. It’s a danger created first and foremost by the extraordinary moment we find ourselves in thanks to both the Russian government and Donald Trump. Russian actors very likely did attempt to hack our voting systems, and did hack the Democratic National Committee, and Clinton campaign chairman John Podesta. They skillfully released that purloined information in order to help Trump win the election. (It certainly did help, though I doubt it was determinative.) All the while, Trump was literally cheering the Russians on, begging them to hack Hillary Clinton even further. That extraordinary public collusion may be all there is, though each time Trump fires an investigator or a White House adviser or cabinet member “forgets” to disclose a meeting with a Russian official, the questions deepen.

So maybe it’s natural, in these absolutely astonishing times, that people will overreact and see Russian malevolence everywhere. That can be a reason, but not a justification. As Masha Gessen said in an interview with Slate this week, “There can be a conspiracy, but the presence of a conspiracy is actually not an excuse for conspiracy thinking. I think that what’s happened to a lot of people on the left, and we’re seeing it now. We’re seeing this sort of re-emergence of Russia as the ultimate toxic paintbrush that you can scare anybody with, and hope that it ends their political career.”

A more nuanced view of Russian malevolence is needed—recognizing that it is no doubt a bad actor, but does not have the capability to buy off every person in our political system. Not everything that goes wrong is thanks to Vlad. Sensible people on the left, a plea: Be careful about what you read. And if you’re a Twitter power-user who keeps seeing your followers spout nonsense, you might want to say something.