But the fact is, there is much more precedent for Congress choosing not to try a former official. The biggest is the case of President Richard Nixon, who resigned ahead of impeachment in 1974. Once Nixon was out of office, the House ended its impeachment proceedings. And then there are judges, who make up most of the impeachments in U.S. history. “On numerous occasions, the target of an impeachment inquiry resigned before the House could take a vote,” wrote Michigan State University law professor Brian Kalt in an extensive 2001 article on late impeachments. “In every one of those cases (except, of course, that of Belknap), the House opted not to proceed.” A footnote in Kalt’s article quoted a 1992 book, Crimes, Follies, and Misfortunes: The Federal Impeachment Trials, by author Eleanore Bushnell, that said, “More than fifty federal judges have resigned while under investigation or after their impeachment had been recommended to the House of Representatives, and further action was not pursued against them.”

So what is stronger precedent, Republicans will ask: A single case — Belknap — or dozens of cases, including one president, in which Congress decided not to pursue impeachment or trial against a former official?

As for the argument that the Constitution does not specifically prohibit the trial of a former president — that when Article II of the Constitution says “The president…shall be removed from office on impeachment…” it didn’t mean just the president in office at the time — the Brian Kalt article quotes an argument from the Belknap trial in which one of Belknap’s attorneys said, “The word ‘president’ appears 14 other times in Article II, and in every single case it is undisputed that it refers to the person serving as president, not to a former president.”