"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..."

"A political message earns reach when people decide to follow an account or retweet. Paying for reach removes that decision, forcing highly optimized and targeted political messages on people. We believe this decision should not be compromised by money. While internet advertising is incredibly powerful and very effective for commercial advertisers, that power brings significant risks to politics, where it can be used to influence votes to affect the lives of millions. 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. All at increasing velocity, sophistication, and overwhelming scale. These challenges will affect ALL internet communication, not just political ads. Best to focus our efforts on the root problems, without the additional burden and complexity taking money brings. Trying to fix both means fixing neither well, and harms our credibility. 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!' We considered stopping only candidate ads, but issue ads present a way to circumvent. Additionally, it isn’t fair for everyone but candidates to buy ads for issues they want to push. So we're stopping these too. We’re well aware we‘re a small part of a much larger political advertising ecosystem. Some might argue our actions today could favor incumbents. But we have witnessed many social movements reach massive scale without any political advertising. I trust this will only grow. In addition, we need more forward-looking political ad regulation (very difficult to do). Ad transparency requirements are progress, but not enough.... This isn’t about free expression. This is about paying for reach. And paying to increase the reach of political speech has significant ramifications that today’s democratic infrastructure may not be prepared to handle. It’s worth stepping back in order to address."

Tweets Jack Dorsey, the CEO of Twitter.