Donald Trump has won the election. Now it is up to America’s institutions, and the people within them, to check his worst instincts.

There is danger in Trump. He’s a man with authoritarian impulses, a conspiracy theorist’s bent, and a taste for vengeance. He has an alarming temperament, little impulse control, and less decency. He has a demagogue’s instinct for finding enemies and a bully’s instinct for finding their weaknesses. He is uninterested in policy, unrestrained by shame, and unbound by norms. He surrounds himself with sycophants and enablers, and he believes both the facts and the falsehoods he finds congenial.

But he is entering an office that is weaker than many realize. For all the same reasons Barack Obama could not bring about the change he had made people believe in, Trump cannot wrench America to his vision of greatness. He is constrained by the House and the Senate, by the Supreme Court, by the executive agencies, and — in ways less formal but no less powerful — by his own staff and party.

If there is hope, it is here: The incentives of governance are different from the incentives of opposition. The Republican majority will have to face the voters in 2018, and then again in 2020. If they have taken health insurance from tens of millions of people without replacement, if they have ripped open families and communities with indiscriminate deportation, if they have embroiled us in disastrous wars or confrontations, if they have sent the economy into tailspin, those elections will not be pleasant.

Perhaps this is a weight Trump will feel in a way he has not over the course of the campaign, and he will change his behavior accordingly. But even if he doesn’t, Republicans have a majority, and it will be one they hope to keep. To keep it, they will need to govern well, or at least convince the electorate they have governed well. And to govern well, they will need to keep Trump’s worst tendencies in check. Now we see how strong the American system really is.