The House will send its impeachment article to the Senate on Monday, Speaker Nancy Pelosi (D-Calif.) has announced, paving the way for another Donald Trump impeachment trial.

The big immediate question is whether the former president will be convicted. The longer-term question — and one that GOP senators are reportedly going to cite among their reasons not to convict — is whether it’s even constitutional to do so.

What’s clear is that this is an unsettled legal question. Only three presidents have been impeached. That includes Trump, for the first time a year ago, and none have actually been convicted. While impeachment trials of other officials have taken place after they left office, there is no final word on whether that was constitutional, and an impeachment trial of a former president has never been attempted.

There is, though, one notable amateur constitutional scholar who has seemingly taken a position on this: Donald Trump. In early 2020, the then-president suggested that former president Barack Obama be impeached for comments that Obama made about health care.

“We should impeach him for that,” Trump said. “Why aren’t we impeaching him?”

Trump, who had just gone through his first impeachment trial, was perhaps joking. But a top congressional ally, Rep. Matt Gaetz (R-Fla.), was entirely serious when he tweeted in response to criticism of his own suggestion that Obama be impeached, “You actually can impeach a former president, FWIW.”

Neither Trump nor Gaetz is actually a constitutional scholar, of course. (Gaetz is at least a lawyer.) But their comments are relevant as the GOP wrestles with a potential strategy to fend off a Trump conviction. And they are suddenly landing the on opposite side of the debate.

Politico’s Andrew Desiderio reports that Republican senators plan to emphasize the argument that Trump’s impeachment trial is unconstitutional. And that makes complete political sense. Convicting Trump would be a very difficult vote for any of them, but absolving him of responsibility for the attempted insurrection at the Capitol isn’t ideal, either — especially given that now-Minority Leader Mitch McConnell (R-Ky.) has indicated a conviction might be warranted. Rather than account for the specifics of the case, why not object on procedural grounds? It might not be the complete “exoneration” that Trump and his allies would desire, nor would it end the threat of Trump’s running again in 2024, but at least it could help avert a chasm in the party.

Sen. Tom Cotton (R-Ark.) seems to epitomize the strategy. While in the immediate aftermath of the Capitol siege he faulted Trump, Cotton seemed to preview the looming votes against conviction by those who might believe Trump bears at least some responsibility.

“The Senate lacks constitutional authority to conduct impeachment proceedings against a former president,” Cotton said in a statement this week. “The Founders designed the impeachment process as a way to remove officeholders from public office — not an inquest against private citizens.”

The Washington Post’s Fact Checker team did a great rundown of the constitutional arguments back when Gaetz made his assertion about impeaching Obama. Most experts interviewed suggested it was possibly constitutional, but only one indicated it was the kind of thing the Founding Fathers might have viewed as a necessity.

Most noted that the chief aim of impeachment is to remove someone for abuse of power, which is off the table once an official is no longer in office. But the impeachment process also allows for Congress to prevent someone who might have committed high crimes and misdemeanors from holding office again — which could give motivation for those facing impeachment to resign early so as not to face that sanction.

“You shouldn’t have a situation where somebody can escape the bar on future officeholding simply by resigning really fast,” impeachment expert Frank O. Bowman III of the University of Missouri School of Law said then. “You could really moot the second remedy in the Constitution.”

Added Ilya Somin of George Mason University, “My personal opinion is probably it could be permissible to impeach somebody who is out of office for the purpose of prohibiting future officeholding.”

In addition, an inability to impeach and convict presidents after they leave office raises the possibility that they could do almost anything they wanted in their final days in the White House, knowing that they wouldn’t face sanctions because there wouldn’t be enough time to impeach and convict.

But just because loopholes might exist doesn’t mean those loopholes aren’t legal or constitutional. Former federal appeals court judge J. Michael Luttig argued in The Washington Post recently that the constitution, in fact, doesn’t allow for impeachment or conviction once out of office.

Article II states that “The President, Vice President and all civil officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.” Article I also states that, “Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold" high office. But Luttig argued that without the former -- removal -- the latter -- disqualification -- doesn’t apply.

“... It is a constitutional impeachment of a president that authorizes his constitutional disqualification,” Luttig wrote. “If a president has not been constitutionally impeached, then the Senate is without the constitutional power to disqualify him from future office.”

The Senate has held impeachment trials for former officials in the past, including Secretary of War William Belknap in 1876. The Senate at the time voted 37-29 that it had jurisdiction, but it failed to reach the two-thirds threshold to convict, so there was no legal challenge to the constitutionality of the proceedings.

“The penalty is removal from office,” Harold J. Krent of the Illinois Institute of Technology’s Chicago-Kent College of Law told the Fact Checker in December 2019. “One could argue that impeachment might still be important if an officer resigns from the office so as to disqualify a former officeholder in the future (for example, Trump could not run again for president), but that seems tangential to the critical separation of powers role that impeachment plays: affording Congress a check on the sitting president.”

That quote has proved prescient when it comes to the current situation, with that being the real punishment Trump could face. Dozens of legal scholars have now signed a letter saying Trump can be convicted in a post-presidency impeachment trial, with the signatories including members of the conservative Federalist Society, along with Bowman and Somin. The letter took no position on whether he actually deserves it.

But as GOP senators consider this as a possible argument against his conviction, it’s worth noting that there is a venue for such debates to happen: the actual courts. Even if the Senate were to convict Trump, that conviction would still be subject to legal review. To the extent a Senate trial resembles a jury trial, the jurors are tasked with deciding a case on the merits rather than the constitutionality of the proceedings. Trump would still have recourse even if he were convicted.

The counterargument to that is that the courts have demonstrated a reluctance to get involved in Congress’s business given the separation of powers issues involved. Courts generally defer to Congress’s “sole power” to set its rules and procedures. Given impeachment is a legal remedy provided to the legislative branch rather than the courts, the judicial branch might decide against intervening.

But as GOP senators face a pretty impossible choice — and might even genuinely disagree with the idea that a former president can be convicted — it’s undoubtedly an attractive position to fall back upon.