Facebook is under fire for political ads. Twitter just banned them completely.

Twitter will ban political ads—both for candidates and for specific issues—starting November 22, according to CEO Jack Dorsey.

The background: Allowing politicians to pay Twitter to reach larger audiences means “forcing highly optimized and targeted political messages” on people, Dorsey tweeted—presenting “entirely new challenges to civic discourse.” He’s right. 

Social-media advertising makes amplifying a message easy for anyone with a little money, allowing misinformation to spread quickly; meanwhile, microtargeted advertising lets people focus messages in ways that only niche groups can see. These features make it easy to spread lies and fool people over social media—and letting politicians do so is not good for democracy. Plus, platforms that accept money for political ads containing lies place themselves in the awkward position of making money from misinformation. 

Not Facebook: Twitter’s policy stands in stark contrast to that of Facebook, which has been heavily criticized over its policy of not fact-checking ads by political candidates. Dorsey even tweeted that it wouldn’t be credible for Twitter to brag about its efforts to fight misinformation if it accepts money for lying political ads—a clear reference to Facebook’s difficult position.

What’s next? Big questions remain.

What does Twitter consider an “issue ad”?  Is an ad from an advocacy group encouraging people to get vaccinated an issue ad? What about an ad about climate change? Who gets to decide? 

The company has said that some exceptions will be made, such as ads to encourage voter turnout. What are the other exceptions?

Will this pressure Facebook into changing its position?

Twitter says it’ll release the final draft of its regulations on November 15. Meanwhile, Facebook execs are writing op-eds about how the company shouldn’t be the gatekeeper of truth on candidate ads.