At the outset of Supreme Court oral arguments, which are being held these days via telephone and live-streamed during the coronavirus pandemic, Chief Justice John G. Roberts Jr. warns everyone to turn off their cellphones.

But he doesn’t remind people to hit the mute button when they’re not speaking. Maybe he will after Wednesday’s arguments in Barr v. American Association of Political Consultants.

That’s because toward the end of the arguments, at about 59 minutes out of the scheduled hour, it sounded as if a toilet was flushing.

To be fair, there’s no proof someone had flushed the toilet during the call. Still, the clunk of some sort of mechanical device followed by the sound of swirling water was evidence enough. “Res ipsa loquitur,” as they say in Latin, “the thing speaks for itself.” Or, to play on the famous quote of the late Justice Potter Stewart on the subject of obscenity, “we know it when we hear it."

The presumed flush came mid-sentence as lawyer Roman Martinez, representing the American Association of Political Consultants, was being questioned by Justice Elena Kagan.

“And what the FCC has said is that when [clunk, swirling water] the subject matter of the call ranges to such topics, then the call is transformed.”

He took no note of it. The justices took no note of it. The transcript took no note of it. Had it occurred in the normal setting for flushes, no one would have taken note of it.

But this was an out-of-context flush. It was the middle of a Supreme Court oral argument, already historic because the lawyers and the justices were all on phones and it was being live-streamed for all to hear, along with the alleged flush.

Funny, too, that the case was all about phones; specifically the question is whether the federal law prohibiting robocalls to cellphones violates the First Amendment’s free speech clause. (The consultants organization, which is challenging the law, is composed of campaign fundraisers, operatives and pollsters, for whom robocalls are important.)

The Supreme Court may be trying to cover up the flush, and who can blame it. The official transcript does not include the flush. On the other hand, transcripts do not indicate when someone has coughed, either.

But it’s not in the official audio of the hearing, available on the court’s website. No clunk. No swirl. (Listen at about 59 minutes and 50 seconds into the recording.)

Those listening in real time were, of course, surprised to hear a toilet flush.

“Did a toilet just flush during #SCOTUS oral arguments?!?” tweeted Kimberly Robinson, the Supreme Court reporter for Bloomberg Law.

“Uh, that sure sounded like a toilet flush in the background of the Supreme Court oral argument,” tweeted Reuters court reporter Lawrence Hurley.

No one has owned up to the flush, if indeed it was a flush.

It could have been anyone on the phone call, or someone near the phone of anyone on the call. It might have been a spouse, or perhaps a child. It could have come from inside a bathroom (let’s not go there) or nearby a bathroom. Fortunately, whatever sounds preceded the flush sound were imperceptible.

But a hunt for the flusher would not be productive. What’s the crime?

And maybe the toilet flushed itself for no reason. Who hasn’t had a toilet that flushed itself from time to time?

The Supreme Court has always resisted live broadcasts of oral arguments, audio or video, out of an apparent concern about people grandstanding or the court becoming a circus. Nobody ever worried about toilet flushes. Will the toilet incident reinforce that resistance?

“Flush-Gate is not in any way an indictment of live-streaming #SCOTUS arguments — at least once the Court is sitting again at One First Street,” tweeted University of Texas law professor Steve Vladeck. “So far as I know, there are no toilets on the bench.”

“If that undignified toilet flush kills the possibility of continuing audio broadcast of #SCOTUS oral arguments when this is over, we’ll need an investigation so I know whom to blame for not using their mute button,” tweeted American University law professor Lindsay Wiley.

And what really was the disruption?

Surely the justices won’t change their views on the merits of the case because of a mere toilet flush.

“To be clear,” tweeted FCC chairman Ajit Pai, “the FCC does not construe the flushing of a toilet immediately after counsel said ‘what the FCC has said’ to reflect a substantive judgment of the Supreme Court, or of any Justice thereof, regarding an agency determination.”

And the justices and the lawyers behaved as if nothing happened. Nobody skipped a beat, as far as we know.

“Who among us has not had a toilet flush during a SCOTUS argument?!” tweeted University of Denver law professor Alan Chen.