For more than two hours on Wednesday afternoon the senators at Donald Trump's second impeachment trial were addressed by a congressman best known for farting on live television and falling for a Chinese honey trap.

Why Democrats would choose Rep. Eric Swalwell to help present their case is a question for Mr. Owl. His role is a perfect illustration of what makes these proceedings so tedious. We are solemnly assured that the trial is the most important thing happening in the world, yet nothing of interest can be said about it. The participants on either side are engaged in a rote mechanical exercise; the outcome is not remotely in doubt.

Two persons who will not be appearing at the trial could have made it a more memorable affair. One of them is the accused himself, whose testimony would at least have been entertaining. The other is Supreme Court Chief Justice John Roberts, whose refusal to preside is more significant than many observers have acknowledged.

As law professor Gregory Mark has pointed out, the Chief Justice's absence not only provides the former president with a specific and at least somewhat plausible legal remedy in the unlikely event that he is not acquitted; if Trump chose to run for office again after being convicted, it would also put the Supreme Court in a very uncomfortable position. "The fates lead the willing and drag the unwilling."

Ever since United States v. Nixon, the high court has made it clear that it considers impeachment a purely political matter that is beyond the purview of its authority. In theory, a conviction by the Senate would not be subject to any kind of legal challenge, much less adjudication by Roberts and his fellow justices.

But if Trump were convicted in this case, he and his lawyers would almost certainly argue that the trial was unconstitutional precisely because Roberts did not preside, directly in contradiction of the plain words of the text, rendering the judgement and the penalty of disqualification from office void. I, for one, am less interested in whether this is a compelling argument than I am in the fact that in what Democrats consider an ideal outcome it would almost certainly be made and would thus require an answer. The precise legal mechanism that would signal such a challenge — the refusal of the Federal Election Commission to file paperwork on behalf of his presidential campaign, a primary ballot access lawsuit — does not matter. Sooner or later, probably long before any actual voting, the courts would have to rule on the question of whether the Senate trial was conducted in a legitimate manner.

I cannot begin to guess how the Supreme Court would rule in such a case (with the exception of Roberts, who would obviously recuse himself). I also suspect that the justices would do almost anything to prevent themselves from having to rule one way or the other. If it had appeared possible even for a moment last month that Democrats were close to the 67 necessary votes to convict Trump, making future Supreme Court litigation on impeachment a near certainty, would Roberts have made the same decision? I doubt it.

Why then did Roberts refuse to participate, creating a highly improbable but logically possible scenario in which Trump would be able to void a Senate conviction? It seems to me unlikely that the Chief Justice had some nefarious motive here. Rather than a sly attempt to preclude the possibility of Trump's conviction and disqualification from office, Robert's decision not to participate strikes me as a tacit rebuke of the process itself, an extra-legal ruling of sorts.

This is not as strange as it might sound. Roberts, whom Trump criticized repeatedly, is probably as ready as millions of other Americans to put the last administration behind him. What he is not so subtly suggesting is that holding a second impeachment trial in as many years is a waste of his time and the country's. It is hard to disagree with the Chief Justice's verdict here.