But impeachment has forced Americans to confront it — a question, it turns out, that was central to the framers’ decision to include impeachment in our Constitution. And Americans overwhelmingly reject what Mr. Trump did, with 75 percent saying in December that his Ukraine extortion scheme was wrong (a view that even some Republican senators have endorsed). That’s huge: For all that divides Americans today, this is a dominant consensus on what it means to abuse public office and distort American democracy.

Americans have also seen that, despite the intense pessimism and even disillusionment that many feel about politics, a political party still can show moral courage — regardless of the political costs. The Democrats were told constantly that impeachment would hurt them in November. Mr. Trump himself has boasted that it will, and what’s more he has relished the chance to claim exoneration and to take a victory lap at the same time as Democratic hopefuls began duking it out in earnest in the primaries. The Democrats knew all this, and what’s more, they knew they faced an uphill battle: That’s what the constitutional requirement of a two-thirds Senate majority to convict imposes from the beginning.

But they still did the right thing. They called out impropriety so glaring that it could not be suffered in silence. And they reminded all of us that a political party can pursue what’s right over what’s expedient — and so can a lone politician, as Senator Mitt Romney showed.