What is noteworthy about the American system of government is not what it can do but what it cannot do. The president is not a tyrant. The separation of powers puts important legal constraints on the executive branch. Federalism puts important legal constraints on what the federal government can impose on the states. The Bill of Rights puts important legal constraints on what any level of government can do to the American people.

Layered on top of those legal constraints is a whole set of bureaucratic norms and procedures that can make it difficult for a president to manage even the executive branch. There are civil service protections for bureaucrats. There are standard operating procedures that officials are loath to contravene. …

When Trump is sworn into office, he will face all of these legal and bureaucratic constraints and more.