Abstract
President Donald Trump threatens American federalism because he sees himself as a popular and powerful populist leader presiding over the unitary executive of a unitary nation. He regards the states as agents of the federal government; therefore, he intervenes, including militarily, in all facets of state and local affairs. He is making unprecedented uses of federal-aid funds to coerce state and local governments into complying with his policies. Federal district and appellate courts have been the principal check on Trump, and he has lost most of the lawsuits filed against his actions. However, 40 months remain in his Administration.