No Wonder the Impeachment Trial Is Such a Mess

President Donald Trump’s impeachment trial has finally begun, complete with 100 senators who serve as both judges and jurors, several members of the House of Representatives who act as prosecutors, a defense team of lawyers, and presiding over the whole affair, the Supreme Court’s John Roberts. All of these people, except for the defense counsel and the chief justice, are politicians who have now either leaped or been forced into a judicial role. This highlights a dangerous characteristic of the impeachment process: It permits, and even invites, the injection of a massive amount of politics into what is, or at least should be, a judicial proceeding. Given that the politics of the past generation has been particularly vitriolic, impeachment thus presents a ripe opportunity for the political element to further weaken the rule of law.

Cynics would say that law and politics have always been hopelessly intermixed, and that impeachment is no different. But the Anglo-American tradition at least has a pretense of keeping the law, the courts, and the judges apolitical, and to some, it’s much more than pretense.

What’s the difference between law and politics anyway? Or perhaps a better starting point is, what’s the difference supposed to be? One of the classic metaphors for explaining the distinction is a ball game. The rules of the game are the law, and the referees are the judges. The players are politicians and other political actors, such as public-interest groups or lobbyists; the teams are political parties; and the ways in which the various players and teams use the rules to get what they want during the game are politics.

But this doesn’t get it quite right, so we need to