Experience in various countries demonstrated that populist leaders enfeeble democracy. Once elected, populist leaders concentrate power in their hands while undermining horizontal checks on their power. By drawing upon the Trump presidency in the U.S., this article reveals one of the dynamics in which populist leaders bypass institutions of horizontal checks in policy-making. It argues that populist leaders use social media platforms to disseminate discourse to convince people that a certain course of action is necessary and thereafter bypass formal institutions in policy-making. Trump used discourse first to discipline the federal bureaucracy, second to roll back Obama-era social and environmental regulations, and third to reorient the US migration policy. His discourse became pervasive thanks to his efficient use of Twitter, which allowed him to achieve political change without going through formal institutional channels.