1) Political leaders flagrantly violate the constitution, typically justifying the power grab as a response to an emergency that the constitution isn’t designed to address.

2) Political leaders faithfully follow constitutional provisions even though the provisions are badly designed, leading to disaster or political paralysis.

3) People or government institutions disagree so intensely on how to interpret the constitution that the struggle surpasses ordinary political conflict; the government might, for instance, use force to stifle mass protests.

Comey’s dismissal is not a constitutional crisis, argued Steve Levitsky, a professor of government at Harvard who recently co-authored an article in Foreign Affairs on why American democracy could erode during Donald Trump’s presidency. “Trump was completely within his constitutional bounds in doing what he did.”