House impeachment managers invited former President Donald Trump to testify under oath at his own Senate trial set to start next week, an offer that would set up one of the nation’s most dramatic political events ever and draw a huge national audience.

“Boy, that would be a dog and pony show,” West Virginia Democratic Sen. Joe Manchin III told reporters Thursday.

But for now, it seems unlikely to happen. And it seems just as unlikely to persuade any additional Republicans to convict Trump on a charge of incitement of insurrection.

Rep. Jamie Raskin, the lead impeachment manager, imbued Thursday’s invitation with a swagger, pointing out to Trump that he has time to testify because he no longer has the official duties of the presidency to carry out.

“We therefore anticipate your availability to testify,” the Maryland Democrat wrote.

The letter underscores how little is known now about what might happen during the trial to make it mild or wild. Could Trump decide to take up the offer and testify? Who else could Democrats decide to call as witnesses? Could there be votes on Senate subpoenas for the president?

Majority Leader Charles E. Schumer and Minority Leader Mitch McConnell are still negotiating the framework of the Senate trial, which would clarify some of these questions.

But Schumer blamed Trump’s revolving-door legal team for holding up the process.

“The impeachment resolution on the trial has been set back because the president keeps switching lawyers,” Schumer said Thursday. “And so we have to negotiate if we want to get it to be bipartisan, his lawyers are part of the deal. But hopefully we can move forward; we’ve had good discussions.”

Raskin’s letter also gives a peek inside his team’s strategy to respond to Trump’s denial of factual allegations in the impeachment charge of incitement of insurrection.

“If you decline this invitation, we reserve any and all rights, including the right to establish at trial that your refusal to testify supports a strong adverse inference regarding your actions (and inaction) on January 6, 2021,” Raskin wrote.

“Adverse inference” is a legal concept that usually plays out in civil lawsuits if one of the parties withholds some evidence, for example if they refuse to testify or if they destroy documents. In those situations, a judge can tell jurors that they can presume the missing evidence would have been bad for the side that didn’t provide it.

House impeachment managers leaned heavily on that concept during Trump’s first impeachment investigation and trial when the Trump administration and witnesses declined to turn over information and fought congressional subpoenas.

The Democrats appear ready to do so again.

Trump’s lawyer, David Schoen, in a letter to Raskin called the invitation a “public relations stunt” and said “there is no such thing as a negative inference in this unconstitutional proceeding.

“Your letter only confirms what is known to everyone: you cannot prove your allegations against the 45th President of the United States, who is now a private citizen,” Schoen wrote. “The use of our Constitution to bring a purported impeachment proceeding is much too serious to try to play these games.”

On the other hand, the letter did not specifically decline the invitation.

And Republicans did not show any signs that they thought Trump would show up or that adverse inference would be persuasive to them when the House didn’t give Trump a chance to respond to the impeachment charge.

“No, I don’t think that would be in anybody’s interest,” South Carolina Republican Sen. Lindsey Graham said of the possibility that Trump would testify. “Just because it’s just a nightmare for the country to do this, it’s just a political showboat move to do this, and they didn’t call him in the House.”

Texas Republican Sen. Ted Cruz said the invitation “just shows that what they’re looking for is a show trial. This is all about partisanship. For four years, the Democratic Party has been defined by hatred for Donald J. Trump.”

Iowa Republican Sen. Charles E. Grassley told reporters that just like the first impeachment, the House didn’t do its work getting evidence and now expects the Senate to do so with witnesses.

That Senate opposition to Trump testifying was bipartisan. Delaware Democratic Sen. Chris Coons called it “a terrible idea.”

When asked why, Coons added only: “Have you met President Trump?”

Katherine Tully-McManus and Dean DeChiaro contributed to this report.