Instead, he’s lashing out at and threatening anyone and everyone who criticizes him, while refusing even to admit that he lost the popular vote. And he’s surrounding himself with people who share his contempt for everything that is best in America. What we’re looking at, all too obviously, is an American kakistocracy — rule by the worst.

What can restrain this rule? Well, Congress still has a lot of power to rein the president in. And it would be nice to imagine that there are enough public-spirited legislators to play that role. In particular, just three Republican senators with consciences could do a lot to protect American values.

But Congress will be much more likely to stand up to a rogue, would-be authoritarian executive if its members realize that they will face a political price if they act as his enablers.

What this means is that Mr. Trump must not be treated with personal deference simply because of the position he has managed to seize. He must not be granted the use of the White House as a bully pulpit. He must not be allowed to cloak himself in the majesty of office. Given what we know about this guy’s character, it’s all too clear that granting him unearned respect will just empower him to behave badly.

And reminding people how he got where he is will be an important tool in preventing him from gaining respect he doesn’t deserve. Remember, saying that the election was tainted isn’t a smear or a wild conspiracy theory; it’s simply the truth.

Now, anyone questioning Mr. Trump’s legitimacy will be accused of being unpatriotic — because that’s what people on the right always say about anyone who criticizes a Republican president. (Strangely, they don’t say this about attacks on Democratic presidents.) But patriotism means standing up for your country’s values, not pledging personal allegiance to Dear Leader.

No, we shouldn’t get into the habit of delegitimizing election results we don’t like. But this time really is exceptional, and needs to be treated that way.

So let’s be thankful that John Lewis had the courage to speak out. It was the patriotic, heroic thing to do. And America needs that kind of heroism, now more than ever.