If there is one central piece of advice that Tribe and Matz would impart, it is this: Impeachment is a political question, not a legal one. Do not imagine that even if you could perfectly know what the Framers meant by “high Crimes and Misdemeanors”—the Constitution’s enigmatic catch-all grounds for impeachment after Treason and Bribery—that you could solve the problem of when or whether to impeach. As they tell it, impeachment may be unwise even when justified. “Under most circumstances, removing the president from office this way is bound to be divisive and disheartening,” they write. “Even when taking that step is fully justified, the price may be higher and the benefits more modest than some would envision.”

So what is to be done? Their answer, in a word, is politics. Grand visions of putting on trial a corrupt or tyrannical or treasonable president “falsely devalue other ways of defending democracy, including popular activism, local and state political engagement, filing lawsuits, donating to civil rights groups, and undertaking private ventures in the public interest.”

The Republicans who failed to remove Andrew Johnson in 1868 did chasten him to cease sabotaging black civil and voting rights in the final year of his presidency. They then elected a replacement more committed to Reconstruction’s goals, Ulysses S. Grant. This is the model they urge the Americans of today to emulate as long as they can.