Over the weekend, Facebook ended up doing exactly what it didn’t want to do: openly feud with a presidential candidate on Twitter.

The fight began after President Donald Trump’s reelection campaign flooded Facebook with ads spreading misinformation about Joe Biden, his son Hunter, and the Ukraine scandal that has dominated the news cycle over the past few weeks. Now, Democrats are firing back directly at the platforms and their rules, rather than simply running counter ads.

The controversy came to a breaking point on Saturday when Elizabeth Warren challenged Facebook’s political advertising policies, exposing the platform’s unwillingness to remove false or misleading ads from politicians. Warren’s ad falsely said that Facebook and its CEO Mark Zuckerberg had endorsed President Donald Trump for reelection in 2020. The ad includes an image of Zuckerberg shaking Trump’s hand in what appears to be the Oval Office.

“We intentionally made a Facebook ad with false claims and submitted it to Facebook’s ad platform to see if it’d be approved,” Warren tweeted. She said that the ad was quickly approved and allowed to run. Warren continued, “Facebook holds incredible power to affect elections and our national debate. They’ve decided to let political figures lie to you.”

We intentionally made a Facebook ad with false claims and submitted it to Facebook’s ad platform to see if it’d be approved. It got approved quickly and the ad is now running on Facebook. Take a look: pic.twitter.com/7NQyThWHgO — Elizabeth Warren (@ewarren) October 12, 2019

As Warren sees it, Facebook’s rules give lying politicians an advantage over other, more truthful candidates. That could favor populists like Trump, whose rhetoric often veers into the realm of conspiracy and disinformation. And since platforms like Facebook can be every bit as important as TV buys, Democrats are starting to realize it’s time to take on Facebook’s policies directly.

Warren has been butting heads with Facebook for some time. Shortly after she put out her big policy plan to break up big tech companies like Facebook and Google, she ran an ad on Facebook showcasing the position. Facebook took down that ad, initially saying that it violated the platform’s advertising policies. After criticism mounted over the move, Facebook reinstated the ad.

In response to Warren’s ad, Facebook tweeted from its PR Twitter account, saying “Looks like broadcast stations across the country have aired this ad nearly 1,000 times, as required by law. FCC doesn’t want broadcast companies censoring candidates’ speech. We agree it’s better to let voters—not companies—decide.”

Warren’s Saturday ad play was the climax after a week of attacks from the Democratic National Committee and Joe Biden’s presidential campaign dunking on social media platforms. The Biden campaign penned letters to Facebook and Twitter requesting that they remove an ad placed by Trump’s reelection campaign making baseless claims that Biden’s son Hunter was facing a corruption probe in Ukraine when the former vice president was intervening to fire a prosecutor there.

None of the ads placed on Facebook, Twitter, or YouTube have been removed as of publication, and the three platforms have all said that they do not violate their advertising policies.

Facebook was the most transparent about their policies, with their public policy director for global elections Katie Harbath writing, “Our approach is grounded in Facebook’s fundamental belief in free expression, respect for the democratic process, and the belief that, in mature democracies with a free press, political speech is already arguably the most scrutinized speech there is.”

“Thus, when a politician speaks or makes an ad, we do not send it to third party fact checkers,” she continued. (Harbath served as a deputy campaign director for Rudy Giuliani in 2008, which has raised eyebrows in some Democratic circles.)

Over the past year, social media sites (primarily Facebook) have faced an onslaught of criticism from Republicans in Washington over baseless concerns that the platforms are unfairly censoring conservative speech. This has forced tech CEOs like Mark Zuckerberg to spend more time on Capitol Hill and speak directly with these lawmakers. On Monday, Politico reported that Zuckerberg has hosted a handful of “informal” talks with conservative pundits and lawmakers like Ben Shapiro and Sen. Lindsey Graham (R-SC).

Democrats are forcing this conversation in public, rather than behind closed doors.

“The DNC in 2020 is running a campaign process to make sure that every single person has an opportunity to demonstrate that they are most qualified to be president, and I don’t believe it would be our role to be airing ads every time there is misinformation,” DNC chair Tom Perez told C-SPAN’s Newsmakers last week.

If a campaign wants to run ads countering misinformation, they’ll have to do it themselves, Perez said.

The DNC’s strategy is to attack the institutions and platforms that are proliferating the ads riddled with mis- and disinformation. Some news outlets like CNN and MSNBC have vowed not to run these ads, so it’s working on that front. However, with how Facebook and Twitter are responding, the Democrats’ calls may fall on deaf ears.