The provisions relating to presidential impeachment have operated as ‘sleeper clauses’ of the United States Constitution. Used only once prior to the proceedings directed against Richard Nixon in 1974, they have created no coherent doctrine of when or even how a president can be impeached and convicted. The four modern episodes of impeachment involving Nixon (1974), Bill Clinton (1998–1999) and especially Donald Trump (2020, 2021) suggest that the flaws in this mechanism for presidential removal embody a genuine failure of the constitutional system. One set of problems involves the confusion between the norms of responsibility that uniquely apply to the president in matters of impeachment and the considerations of due process that apply in other legal proceedings. But the deeper challenges rest on the impossibility of inducing Congress to perform its constitutional duty when expedient political calculations routinely intervene.