Consider two scenarios about how Washington works. In one, a local activist decides to run for Congress. A friend hosts a fund-raiser for her at his law firm, where 10 partners each give the maximum legal individual donation, $2,800. After she wins, the host asks her to meet with a client, a constituent whose business would be affected by legislation her committee will soon vote on. She agrees to hear the company’s case against the bill. She never hears from anyone on the other side, which has no lobbyists, and she votes for an amendment that weakens the bill.

In the second, a man elected to high office directs a meeting of foreign leaders to be held at a resort he owns. He ignores subpoenas, dangles pardons to staff members to encourage them to violate the law and to former employees to discourage them from cooperating with investigations. He appoints industry lobbyists to positions where they reverse regulations affecting their former employers. (This list could go on.)

Both of these are stories of corruption. In both, the public interest is distorted by money. But are they aspects of the same story, just different corners of a single big swamp, one deeper than the other? Or are they different in kind, and not just degree?

Donald Trump’s 2016 chant “Drain the swamp,” which most often seemed to refer to the independent institutions of government, has been embraced as a metaphor across the political spectrum and in the media to refer to the pervasiveness of corruption. In this version, the undifferentiated “swamp” matters more than the gradations along the wide scale from the new member of Congress desperate for campaign funds to the raw plunder of Mr. Trump, his family and allies.