The most haunting part is that if a courageous whistle-blower hadn’t come forward, Trump most likely would have gotten away with it. He would have pressured the Ukrainian government to announce an investigation of the Bidens, and we in the media would have played along, producing the headlines that Trump wanted to see.

4. Impairing the administration of justice.

That phrase appears in the second impeachment article against Nixon, which detailed his efforts to use the I.R.S., F.B.I. and others to hound his opponents. It’s a version of abuse of power — but distinct from the previous item because it involves using the direct investigatory powers of the federal government.

Trump has repeatedly called for investigations against his political opponents, both in public and in private with aides. For example, as the Mueller report documented, he pressured Jeff Sessions, then the attorney general, to investigate Hillary Clinton: “You’d be a hero,” Trump said. This behavior has violated the constitutional rights of American citizens and undermined the credibility of the judicial system.

5. Acceptance of emoluments.

The Constitution forbids the president from profiting off the office by accepting “emoluments.” Yet Trump continues to own his hotels, allowing politicians, lobbyists and foreigners to enrich him and curry favor with him by staying there. On Sunday, William Barr, the attorney general, personally paid for a 200-person holiday party at Trump’s hotel in downtown Washington.

The Democratic-controlled House has done an especially poor job of calling attention to this corruption. It hasn’t even conducted good oversight hearings — a failure that, as Bob Bauer, an N.Y.U. law professor and former White House counsel, told me, “is just astonishing.”

6. Corruption of elections.

Very few campaign-finance violations are impeachable. But $280,000 in undisclosed hush-money payments during a campaign’s final weeks isn’t a normal campaign-finance violation. The 2016 election was close enough — decided by fewer than 80,000 votes across three swing states — that the silence those payments bought may well have flipped the outcome.

7. Abuse of pardons.

The president has wide latitude to issue pardons. But Trump has done something different: He has encouraged people to break the law (or impede investigations) with a promise of future pardons.