But President Donald Trump’s increasingly incendiary Twitter feed, which remains outside Kelly’s control, has short-circuited that attempt at creating a functional system for controlling the flow of information into the Oval Office.

Twitter has allowed the president to continue accessing fringe websites and viewing racist videos simply by scanning his “mentions,” according to two former aides who have observed how he uses the site. Trump doesn’t use the direct-message function on the website, which would allow people he follows to privately share links with him — but he often looks at tweets that mention his handle, and picks up links and videos there.

The conversation on Twitter then often dictates his thinking. “Everybody’s talking about this,” he will tell his top aides in the West Wing, referring to a clip or an article he saw circulating among the small group of Twitter users he follows.