Attorneys for former President Trump on Thursday dismissed the prospect of him testifying at his Senate trial next week after Democratic impeachment managers requested that he do so under oath.

"We are in receipt of your latest public relations stunt. As you certainly know, there is no such thing as a negative inference in this unconstitutional proceeding," attorneys Bruce Castor and David Schoen wrote to lead impeachment manager Rep. Jamie Raskin (D-Md.).

"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," the letter continued. "The use of our Constitution to bring a purported impeachment proceeding is much too serious to play these games.”

The letter did not explicitly say Trump would not testify, but Jason Miller, a senior adviser to Trump, later said unequivocally that the former president would not participate.

"The president will not testify in an unconstitutional proceeding,” Miller said in a statement.

Raskin, in a statement issued late Thursday, said Trump's refusal to testify "speaks volumes and plainly establishes an adverse inference supporting his guilt."

"Despite his lawyers’ rhetoric, any official accused of inciting armed violence against the government of the United States should welcome the chance to testify openly and honestly—that is, if the official had a defense," Raskin said.

Trump's second impeachment trial is set to begin next week. The House last month impeached the former president for inciting violence against the government over his role in the Jan. 6 riot at the Capitol, which also claimed the life of a police officer.

Raskin sent a letter to Trump and his attorneys earlier Thursday alleging that the former president’s defense denies irrefutable facts about Trump’s role in the deadly insurrection.

To clear up the alleged discrepancies, Raskin asked Trump to testify, and face cross-examination, as early as Monday and not later than Feb. 11, suggesting that the testimony would not necessarily be in the Senate chamber or even in public. 

The Democratic impeachment managers outlined their case in a legal brief filed this week, in which they argued Trump was “singularly responsible” for the Capitol attack. 

While their impeachment effort comes too late to remove Trump from the White House, they argue that it remains crucial to convict him, both to prevent him from holding public office again and to send a message about boundaries of conduct to future presidents. 

Trump spent weeks falsely claiming the 2020 presidential election was stolen from him, even as courts dismissed his team's allegations of voter fraud. The president on Jan. 6 urged his supporters to march to the Capitol to stop the certification of votes affirming Joe Biden as the next president. A mob overwhelmed law enforcement and stormed the Capitol a short time later.

Trump's attorneys argued in their own legal brief that Trump is constitutionally ineligible to face an impeachment trial because he’s no longer in office. They added that even if senators found the proceedings constitutional, his comments were protected under the First Amendment. In the brief, the attorneys indicated Trump still believes the election was stolen.

Updated at 9:21 p.m.