Twitter announced the details of its new political advertising policy on Friday, and once it goes into effect this month, politicians won’t be able to run false ads on Twitter. But they also won’t be able to run ads that correct the spread of misinformation.

Oil and gas companies will be able to continue promoting fossil fuels, but environmental advocacy organizations won’t be able to run ads supporting a carbon tax. And when President Trump tweets about the strength of the economy or about alleged corruption by a political opponent, no opposition candidate can run an ad on Twitter to counter the enormous organic reach of the person holding the highest elected office in the country.

During the 2020 election cycle, on a platform that is one of the greatest technological innovations in free expression in our lifetimes, candidates won’t be able to use ads to speak their views on political issues or gain access to wider audiences, and advocacy organizations won’t be able to use ads to push for legislative changes. (Twitter will allow ads related to social causes such as climate change, gun control and abortion, though these ads will be subject to restrictions on targeting.) They can do these things with TV ads. Or radio ads. Or newspaper ads. Or Facebook ads. But they won’t be able to do them on Twitter.

Political advertising has long been controversial, but broad bans on digital platforms will harm our democratic process by silencing voices and reducing the range of views that reach voters. Digital advertising plays a particularly important role in political communication in an era of heightened media choice and fragmented public attention. Tech platforms have greatly lowered the costs of running political advertising. No longer do candidates need to invest significant sums of time and money to produce and buy 30-second television spots or take out full-page ads in newspapers.