What kind of spectacle is the impeachment trial before the Senate of Donald J. Trump? In its opening days, the audience was given two wildly different but equally bathetic prompts as to how we should see it. We were invited by two central figures to understand it, on the one hand, as a proceeding of exquisite gravity and, on the other, as a bad TV show. For its presiding officer, Chief Justice John Roberts, the trial ought to be imagined as an earnest weighing up of truth and lies by a most august assembly. Near the end of the first long day’s session, he admonished Trump’s prosecutors and defenders “to remember that they are addressing the world’s greatest deliberative body.” To give them a sense of the standards that used to apply in such proceedings, he referred to the impeachment of a judge, Charles Swayne:

In the 1905 Swayne trial, a senator objected when one of the managers used the word “pettifogging” and the presiding officer said the word ought not to have been used. I don’t think we need to aspire to that high a standard, but I do think those addressing the Senate should remember where they are.

But we do not need to go back to 1905 to be reminded where we all are now. On the morning of the second day of the trial, its central figure, Trump himself, issued a decorous tweet:

After having been treated unbelievably unfairly in the House, and then having to endure hour after hour of lies, fraud & deception by Shifty Schiff, Cryin’ Chuck Schumer & their crew, looks like my lawyers will be forced to start on Saturday, which is called Death Valley in TV.

The fall from a discourse in which “pettifogging” might sound like an unseemly breach of high civility is vertiginous, but this is also a shift of genres. Roberts wished to dress the senators in togas and place them in a historical drama, leaning forward with their hands on their chins, as if listening intently to Cicero or Seneca. Trump’s complaint was that his wrestling match against Shifty Schiff and Cryin’ Chuck would be shown in a crappy television time slot.

Everybody knows that Trump is much nearer the mark. For all of Roberts’s grandiosity, the idea of this Republican-controlled Senate as the world’s greatest deliberative body—ludicrous at the best of times—is being relentlessly undermined by the very proceedings he is presiding over. It has been clear even before this trial began that it is, for the majority of senators, an exercise in self-abasement by what is supposed to be a mighty force for holding the executive to account. As Mitch McConnell told Sean Hannity on Fox News in mid-December, the Republican majority has positioned itself merely as an arm of the presidency: “I’m coordinating with White House counsel. There will be no difference between the president’s position and…