CNN  — 

To many Senate Republicans, including Senate Majority Leader Mitch McConnell, there’s no question in their minds: President Donald Trump committed impeachable offenses.

But getting McConnell and at least 16 other Republicans to convict Trump after he’s left office is another question entirely.

“There is no love lost within the Senate Republican Conference for Trump,” said one GOP source familiar with internal discussions. “Everybody is ready for this to end. But there is a really open question about how many people will vote to convict him after his term will have expired.”

Several senior GOP sources told CNN on Thursday that many Republicans are torn over whether Trump’s actions warrant the unprecedented step of prohibiting him from ever serving in office again after he leaves the White House next week.

Republicans say it will ultimately be up to a combination of factors – the case built by House impeachment managers, whether new information comes out about Trump and the deadly Capitol riot and whether emotions are still raw when it comes time to vote – to determine whether Republicans will break ranks and end Trump’s political career for good.

Privately, Republicans have reviewed internal polling showing Trump’s support cratering among GOP voters since Election Day – especially since last week when he incited a violent mob of his supporters to riot in the Capitol leading to the deaths of five people, two sources said. But even after he leaves office, he is bound to still maintain significant sway with the GOP base, something Republicans facing reelection – and potential primary challengers – will be forced to confront.

Republicans are by and large split into several camps. Some, like Arkansas Sen. Tom Cotton, oppose the proceedings because, they argue, it’s constitutionally dubious to convict a President once he leaves office, a position many Republicans are bound to take.

“I doubt we can even have a trial for a former President, which is what we are dealing with here,” GOP Sen. Kevin Cramer of North Dakota told CNN on Thursday.

Others, such as Sen. Tim Scott of South Carolina, are likely to align with many House Republicans who said that the impeachment proceedings will further divide the country.

“An impeachment vote will only lead to more hate and a deeply fractured nation,” Scott, who is facing voters in 2022, said this week.

Yet, some Republicans say that it’s critical to lay down a marker to make clear that Congress will not stand for future presidents who may follow Trump’s path – and that the President’s actions crossed a clear line that must never be replicated again.

“I believe that this President has committed an impeachable offense,” Alaska Sen. Lisa Murkowski told Alaska television station KTUU on Wednesday, adding that it would be “appropriate” for the Senate to bar him from holding office again.

“I think that is one of the most consequential actions that we should take, and I think that would be appropriate.”

In a statement Thursday, Murkowski said she would “listen carefully” to the arguments before making a decision on her vote, but said the House acted “swiftly, and I believe, appropriately with impeachment.”

McConnell, for one, has privately told his colleagues he is genuinely undecided and will keep an open mind when listening to the arguments presented by House Democratic impeachment managers, according to people familiar with the matter. He wants to let the passions of the moment cool down and let the trial play out before taking a position that many view will be the key in swaying Senate GOP votes – and determining whether Trump is convicted.

“There is no difference in the (GOP) conference that there are potentially impeachable offenses here,” the first Republican source said. “I think almost everybody believes that.”

Indeed, many remain sharply critical of Trump’s remarks to his supporters at the rally last week that preceded the Capitol riot.

“If anything, he urged in a very emotional situation, very inappropriate action by people that appear to be his supporters,” said Sen. Mike Rounds, a South Dakota Republican, after the rioters stormed the Capitol.

Republican senators, who are out of Washington until next week, are mostly keeping quiet ahead of the trial. More than a dozen Senate GOP offices either declined or did not respond to requests for comment Thursday on the House’s approval of an article of impeachment, which charged Trump with inciting an insurrection and was backed by 10 House Republicans.

Democrats weigh whether to bring witnesses, plan to argue constitutional merits

House Democrats, recognizing that they have to convince at least 17 Republicans to go along with conviction, are beginning to build their case internally. Among the questions they’re trying to resolve: Whether to bring in outside witnesses, including Georgia Secretary of State Brad Raffensperger, whose interaction with Trump was cited in the impeachment article after the President pressured the Republican election official to “find” the votes necessary to overturn Joe Biden’s victory in the state.

“We’ll get you answers as we get some answers,” Raskin said Wednesday night when asked if he would seek witnesses in the impeachment trial as he walked into House Speaker Nancy Pelosi’s suite.

Walter Jones, a spokesman for the Georgia secretary of state, wouldn’t say Thursday if Raffensperger or another top election official, Gabriel Sterling, would be willing to testify at the trial.

“Our team is fully focused on the current session of the Georgia General Assembly at the moment,” Jones told CNN.

Raskin, a constitutional scholar, is expected to argue that there is ample precedent for the Senate to convict a federal official after leaving office – a case central to convincing some fence-sitting GOP senators since Trump’s defense team is expected to argue such an action is unconstitutional.

“Whether or not the Senate has the constitutional authority to hold an impeachment trial for a President that is no longer in office is debatable,” said Sen. Pat Toomey, a Pennsylvania Republican who emerged as a leading GOP critic of Trump’s post-election rhetoric. “Should the Senate conduct a trial, I will again fulfill my responsibility to consider arguments from both the House managers and President Trump’s lawyers.”

There’s never been an impeachment trial for a former president, and Trump’s allies have argued the Senate doesn’t have the constitutional authority to hold a trial for the President once he’s left office. The Senate has only convicted eight officials in history.

“The Constitution specifically says the President shall be removed from office upon impeachment. It doesn’t say the former president,” Alan Dershowitz, a member of Trump’s first impeachment legal team, told Fox News’ Maria Bartiromo. “Congress has no power to impeach or try a private citizen.”

But several constitutional scholars say that’s not true. Stephen Vladeck, a CNN analyst and University of Texas law professor, noted in a New York Times op-ed Congress impeached and tried a secretary of war in 1876 after he had resigned, and the Senate concluded it had the power to try former officers.

The Constitution, Vladeck noted, says the Senate’s judgment in impeachment cases includes removal from office as well as “disqualification to hold and enjoy any office of honor, trust or profit under the United States.”

“That latter clause is the key, because it drives home that the Senate has two decisions to make in impeachment cases: First, it must decide whether an officer should be removed,” Vladeck wrote. “Then it must decide whether this person should be disqualified from holding any future federal office. Indeed, of the eight officers the Senate has ever voted to remove, it subsequently voted to disqualify only three of them — reinforcing that removal and disqualification are separate inquiries.”

McConnell, in his statements about the upcoming trial, has not suggested that he thinks it would be unconstitutional or that he would make any effort to stop the trial on those grounds. Still, Republicans, including McConnell, may ultimately be swayed by the arguments and could point to Trump’s status as a former president as a reason not to vote to convict him.

In a memo obtained by CNN laying out the timeline for impeachment, McConnell did not question whether the trial should happen. But he did raise a question that doesn’t yet have a clear answer: Whether Chief Justice John Roberts would preside like he did for Trump’s first impeachment trial.

“When a sitting President is tried by the Senate, the Constitution requires that the Chief Justice preside over the trial. The Senate Impeachment Rules require that the Senate invite the Chief Justice to attend the Senate and preside over the trial,” McConnell wrote. “Ordinarily, that invitation would issue on January 19. Whether the Chief Justice would actually preside over the trial after President Trump ceases to be President on January 20, however, is unclear.”

Trump sees GOP support erode as Republicans eye primaries

Even as GOP support for Trump has begun to deteriorate, many Republicans have to worry about political ramifications back home. One GOP source said an internal poll since Election Day has seen Trump slide more than double digits among Republican voters nationally.

Still, Trump supporters are bound to be a force in GOP primaries – and how they vote on conviction is likely to set the tone for the election cycle.

The landscape is challenging for Senate Republicans, when they must defend 20 seats compared to 14 for Democrats. Senate Republicans up for reelection who find Trump guilty could easily be facing Trump-backed primary challengers. Before the riots, Trump was already demanding a primary challenge to the Senate’s No. 2 Republican, John Thune of South Dakota, for saying the President’s efforts to overturn the election would fail.

“You just got to take things in stride,” Thune said, leaving the Capitol the night of the riots, when asked if he were worried about a primary challenge. “It’s a free country. I suspect that we’ll see a lot of that activity in the next couple of years for some of our members – myself included perhaps. You just got to play the hand you’re dealt.”

While Trump has been significantly weakened politically in the fallout from the riots he incited, there’s still likely to be a loyal pro-Trump base in the Republican Party after he leaves office. Among those in cycle being watched closely: Roy Blunt of Missouri, Rob Portman of Ohio and Todd Young of Indiana.

Many are staying mum on how they might come down.

“I believe we need to wait and hear the evidence,” said Alabama Sen. Richard Shelby, the 86-year-old veteran Republican who could retire rather than seek reelection in 2022. “And as a juror, I would carefully consider the evidence presented.”

CNN’s Alex Rogers contributed to this report.