The social media site Twitter is to stop showing all political advertising globally.
The company's CEO Jack Dorsey made the announcement on the platform on Wednesday.
However, there will be some exceptions, such as adverts in support of voter registration.
He explained the move, which comes into effect next month, in a series of tweets.
He said: "We believe political message reach should be earned, not bought."
"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."
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
He added: "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."
He also said the platform considered only stopping candidate adverts, but that issue adverts were a way to get around this.
He said: "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."
He added that while advert transparency requirements are progress, these are "not enough."
"The internet provides entirely new capabilities, and regulators need to think past the present day to ensure a level playing field."
He said the firm will release its policy on this new ban by November 15th, with it coming into force on November 22nd.
It will also give advertisers a notice period before this change goes into effect.
In a final tweet, Mr Dorsey said: "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."
The website currently permits political advertising, including political campaigning and issue advertising.
But all political content must comply with laws in relation to disclosure and content requirements, eligibility restrictions and blackout dates for the countries where they advertise.
Back in 2017, Twitter announced changes to the ways adverts were displayed.
At the time, the company said the increased transparency would apply to political and issue-based ads.
This included details behind the ads and tools to share feedback.