For one of the first times since the election, Bernie Sanders just had a really rough week. The Vermont senator made a series of bone-headed remarks, which while not particularly painful at the moment, could cost him if repeated in the future.

Sanders is a front-runner in the 2020 race if he decides to declare his candidacy and it certainly looks like he’ll take another run at the Oval Office. He’s been testing the waters, popping up in all the key battleground states, including a rally in Michigan last Sunday. During that appearance, he teased his 2020 platform and railed against the Republicans’ tax bill but ignored the stumbles he fell into during the previous week.

The senator’s problematic week began with an appearance on Meet the Press on Feb. 18, when he made two remarks that had probably had his communications team smacking themselves in the head later. First, he claimed that “40 percent of the guns in this country are sold without any background checks.” That’s an outdated statistic, which the Washington Post deemed a “zombie fact” and it earned him four of the paper’s dreaded “Pinocchios.”

In that same interview, Sanders had another slip-up.

In the wake of the latest Robert Mueller indictment, it was revealed that Russian actors were supporting his candidacy to sow divisiveness.

On Meet the Press, Sanders claimed that his campaign warned Clinton about Russian interference. Sanders said that “one of our social media guys in San Diego actually went to the Clinton campaign in September and said something weird is going on.”

Unfortunately for Sanders, that’s not exactly what happened. The staffer that he referenced, John Mattes told Politico that he went to a pro-Clinton PAC, not the Clinton campaign. He also noted that he decided to contact the Clinton backers on his own, without the direction of Sanders’ team.

Later in the week, during an interview with Vermont Public Radio, Sanders repeated his mistaken claim that Mattes contacted the Clinton team and even said that Mattes told Clinton’s campaign, “I think these guys are Russians.”

He also attacked Clinton’s response.

“The real question to be asked is what was the Clinton campaign [doing about Russian interference]? They had more information about this than we did. They were supporting my campaign? No. They were attacking Hillary Clinton’s campaign and using my supporters against Hillary Clinton.”

Sanders’ misstep on Vermont Public Radio prompted a lengthy statement from his press shop in which he condemned Russia’s interference in the 2016 election.

https://twitter.com/gdebenedetti/status/966453203020779521

During his Meet the Press interview, Sanders also criticized President Barack Obama’s administration for not being more “public” and “aggressive” about Russian meddling. And while Obama is out of the political arena as a candidate, he’s still a revered figure in the Democratic party and one of the Dem’s great hopes for uniting the progressive and establishment factions.

When Politico reached out to the Vermont lawmaker’s team for a comment, spokeswoman Arianna Jones instead criticized Politico’s reporting, saying that Bernie “is not a great fan of reporters who try to provoke controversy where none exists.”

The idea that Politico unfairly sexes up politics is an old gripe of the swamp, but nevertheless, it’s not the wisest move to criticize Politico reporters to their faces.

During the 2016 election, Bernie styled himself as a politician eager to talk about the facts and how only the facts that matter. When Clinton’s email scandal was brought up during a debate he said, “the American people are sick and tired of hearing about your damn emails.” Moments later, he shouted “enough about the emails, let’s talk about the real issues facing America.”

Facts are probably a dead language in the Trump-era but if Bernie wants to win in 2020 or at least have the credibility to propel a like-minded candidate into the Oval Office, he can’t afford slip-ups like those he had last week. Sanders built his grassroots campaign as an honest candidate who tells the truth.

Bernie’s status as a political rogue also took a hit last week when his son, Levi, announced his intention to run for Ccongress in New Hampshire. The Democratic party has grown weary of political dynasties—that was one of the main criticisms laid upon Joe Kennedy III when the Democrats tapped him to deliver their State of the Union rebuttal. If the Sanders name becomes attached to a political dynasty, that could be another rhetorical bullet that challengers would fire across his bow during the primary race.

For now, those millions of Americans still feelin’ the Bern should just hope that Bernie has his facts together the next time somebody sticks a microphone or camera in his face.