But President Trump’s conduct regarding Ukraine was different. Here was a president, operating at the absolute apex of his constitutional powers, steering international diplomacy for personal benefit, and not only were there no clear means of constitutional restraint, there was obvious intent to accomplish the scheme well outside the public eye. The scheme was blocked by the unlikely combination of whistleblowing and informal political pressure. Even worse, a defiant administration refuses to admit to any wrongdoing at all—even calling the key piece of evidence against the president a “perfect” call. It was essentially our good fortune (through the courage of the whistleblower) that the American people have access to partial information about the scandal so they can factor it into their electoral calculus.

What’s the constitutional check for misconduct of that kind? Citizens can’t run to court to block this particular abuse of presidential power. We can’t even count on public knowledge for public accountability. The administration is still actively holding back material evidence.

The checks and balances of the American constitutional republic are far-reaching, and the framers—in their wisdom—established an ultimate check on the president. When no other structure of government can restrain his abuse of power, Congress can impeach him and remove him from office. When presidents promulgate unlawful rules and regulations, we can take them to court. When presidents announce unpopular policies, we can vote for their opponents. When presidents work in secret to substitute their personal priorities for the public good in a strategically vital region of the world, the conventional checks are unreliable. In that context, impeachment is the difference between punishment and permission when a president abuses his power while conducting affairs of state.