On 20 October 2020, prior to the US presidential election, Twitter modified its user interface for sharing social media posts. In an effort to reduce the spread of misinformation on the platform, the new interface nudged users to be thoughtful about the content they were sharing. Using data on over 160,000 tweets by US news media outlets, we show that this policy significantly reduced news sharing, but that the reductions varied heterogeneously by political slant: sharing of content fell significantly more for left-wing outlets relative to right-wing outlets. Examining Twitter activity data for news-sharing users, we find that conservatives were less responsive to Twitter’s intervention. Lastly, using web traffic data, we document that the policy significantly reduced visits to news media outlets’ websites.