CEO Jack Dorsey just announced, via tweet, that Twitter will be banning all political advertising — albeit with “a few exceptions” like voter registration.

“We believe political message reach should be earned, not bought,” Dorsey said.

While it’s not totally clear how broad those exceptions will be, it sounds like the ban will apply to both ads endorsing candidates and ads advocating a position on political issues.

Dorsey said the company will share the final policy by November 15, and that it will start enforcing that policy on November 22.

“Internet political ads present entirely new challenges to civic discourse: machine learning-based optimization of messaging and micro-targeting, unchecked misleading information, and deep fakes,” he wrote. “All at increasing velocity, sophistication, and overwhelming scale.”

We’ve made the decision to stop all political advertising on Twitter globally. We believe political message reach should be earned, not bought. Why? A few reasons…🧵 — jack 🌍🌏🌎 (@jack) October 30, 2019

So why not continue accepting ads while trying to stamp out misinformation? He argued that the company “needs to focus our efforts on the root problems, without the additional burden and complexity taking money brings.”

A blanket policy could also help Twitter avoid the headache and controversy of making these determinations of truthfulness on a case-by-case basis.

This comes after Facebook, in particular, has faced heavy criticism around its refusal to fact-check political advertising (even as it took steps to fight election-related misinformation elsewhere), with Facebook employees writing an open letter objecting to the company’s stance.

At the same time, one of the ads that prompted the recent controversy — in which the Trump campaign promoted a conspiracy theory about Joe Biden — also ran on YouTube and Twitter (and on some TV networks, although CNN refused to air it).

So even though the discussion has focused on Facebook, the broader questions of permissiveness and responsibility are ones that all the major internet platforms have to face.

Over the summer, in fact, Twitter said it would start blocking state-run media outlets from running ads on its platform after it identified an operation to “sow political discord” around the protests in Hong Kong, which involved hundreds of accounts linked to the Chinese government.

The idea that Facebook should just ban all political ads is a solution that’s been floated by a number of pundits, including our own Josh Constine. Before today, that might have seemed like an extreme or unrealistic step. Suddenly, it looks much more possible — or at least like Mark Zuckerberg will have to keep answering questions about this for a while.

Dorsey didn’t mention Facebook by name in his tweets, but he seemed to allude to the company’s position when he wrote, “For instance, it‘s not credible for us to say: ‘We’re working hard to stop people from gaming our systems to spread misleading info, buuut if someone pays us to target and force people to see their political ad…well…they can say whatever they want! 😉'”

It’s also interesting that Twitter chose to announce this just as Facebook released its latest earnings report.

Dorsey also acknowledged that Twitter is “a small part of a much larger political advertising ecosystem,” but he said, “We have witnessed many social movements reach massive scale without any political advertising. I trust this will only grow.”

In a statement, eMarketer senior analyst Jasmine Enberg said the move is “in stark contrast to Facebook,” but also noted “it’s likely that political advertising doesn’t make up a critical part of Twitter’s core business.”