Dems set to prosecute case at Trump impeachment trial amid speculation over which Republicans might convict

The House impeachment managers will begin their opening arguments on the merits of the impeachment of former President Donald Trump when the chamber convenes at noon on Wednesday, following a 56-44 Senate vote to move ahead with the trial Tuesday. 

Meanwhile, speculation is running rampant about which Republicans may vote to convict Trump. The attention has mainly been on a group of moderate senators, but also includes Senate Minority Leader Mitch McConnell, R-Ky. Bloomberg reported Tuesday that McConnell hasn't decided how he'll vote on the final conviction question and has told other Republicans that their vote is a personal decision. 

That's consistent with previous comments by McConnell that have been reported. And a source close to McConnell told Fox News that there's nothing new he's saying or doing "at all other than his vote yesterday on Constitutionality, which in itself, was a repeat of the vote from the week before."

It's almost certain that 17 Republicans won't vote to convict Trump -- the number necessary for Democrats to reach the 67-vote supermajority threshold. That's bolstered by the fact McConnell and 43 other Republicans voted Tuesday that the impeachment trial is unconstitutional. But the House impeachment managers are hopeful they can get more Republicans on board to deliver a stronger rebuke to the former president. 

They made some progress in that direction Tuesday when Sen. Bill Cassidy, R-La., switched his vote from against the trial's constitutionality in a test vote forced by Sen. Rand Paul, R-Ky., last month to in favor of constitutionality. Cassidy had said his previous vote "was a vote in a moment in time" and that his Tuesday vote was because "the House managers had much stronger constitutional arguments. The president’s team did not."

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"We were told that it would be completely partisan and locked from the last vote and it wasn’t, so people's minds are open," lead House impeachment manager Rep. Jamie Raskin, D-Md., said. "We haven't started the evidence yet, but we're starting tomorrow."

The impeachment managers are expected to make the case that Trump is fundamentally responsible for the attack on the Capitol by a mob of his supporters that resulted in multiple deaths and forced hundreds of lawmakers and former Vice President Pence into hiding -- interrupting the certification of the 2020 presidential election result. 

"After spending months propagating the lie that the 2020 election had been stolen from him, President Trump summoned his supporters to a rally in Washington on January 6," the impeachment managers said in a brief Tuesday, offering a preview of their trial argument. "Against this backdrop, President Trump addressed a crowd that he knew was armed and primed for violence. He falsely raged to the crowd that the Joint Session was the culmination of a treasonous plot to destroy America. He exhorted his supporters to "fight like hell [or] you’re not going to have a country anymore."

They continued: "And he urged the mob to march to the Capitol, telling them that "[y]ou’ll never take back our country with weakness. He thus lit the match of insurrection and threw it into the powder keg he had spent months creating." 

Senate Majority Leader Chuck Schumer, D-N.Y., not an impeachment manager but one of their key supporters in the upper chamber, said Tuesday that Trump fed "the mob the lies that motivated their behavior."

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The five senators initially getting the most attention as possible conviction votes were Sens. Mitt Romney, R-Utah; Susan Collins, R-Maine; Ben Sasse, R-Neb.; Pat Toomey, R-Pa., and Lisa Murkowski, R-Alaska. This is because they are all well-known Trump critics within the GOP and they all voted for the trial's constitutionality last month. Cassidy joins the group under watch for a vote to convict after his Tuesday vote to move ahead with the trial. 

Cassidy made clear Tuesday, however, this his initial vote "is not a prejudgment on the final vote to convict."

Democrats are expected to make a highly visual case on Trump's responsibility for inciting an insurrection, the fundamental charge in the article of impeachment. On Tuesday, they played a graphic video of the events of Jan. 6 to a solemn Senate chamber, showing Trump's inflammatory rhetoric at his rally that day, his supporters saying he sent them to the Capitol and the damage done by the mob. 

They'll also aim to parry arguments from the Trump legal team that the impeachment was not done fairly and that his actions were protected by the First Amendment, among others. 

"The events that form the basis for President Trump’s impeachment occurred in plain view. They are well known to the American people," the impeachment managers wrote in a brief, addressing the due process argument. "Many Members of Congress were themselves witnesses to his conduct and its consequences. There is no basis on which President Trump could assert that what a horrified Nation saw with its own eyes, and heard with its own ears, is somehow 'fake news.'" 

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"The First Amendment has no application in an impeachment proceeding, which does not seek to punish unlawful speech, but instead to protect the Nation from a President who violated his oath of office and abused the public trust," the impeachment managers said on Trump's First Amendment argument.

They add: "President Trump attempts to equate his January 6 speech to statements by other politicians, arguing that convicting him will chill political speech. But context matters under the First Amendment. While other political figures have used heated rhetoric, none of the speeches that President Trump cites bears any resemblance to President Trump’s anti-democratic effort to prolong his presidency by exhorting a mob to attack the Congress."

Trump's lawyers, however, say that the trial is "political theater" and that his Jan. 6 comments do not comport with Democrats' narrative that he incited the crowd to storm the Capitol. 

There is no basis on which President Trump could assert that what a horrified Nation saw with its own eyes, and heard with its own ears, is somehow 'fake news.'

— Brief from House impeachment managers

"Mr. Trump spoke for approximately one hour and fifteen minutes. Of the over 10,000 words spoken, Mr. Trump used the word 'fight' a little more than a handful of times and each time in the figurative sense that has long been accepted in public discourse when urging people to stand and use their voices to be heard on matters important to them; it was not and could not be construed to encourage acts of violence," Trump's lawyers said in a brief filed Monday. 

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The House managers have up to 16 hours over the court of two days to make their case to the senators, although they may take less time. Then Trump's legal team will have the same opportunity. 

By this time, the trial will likely be bleeding into the weekend, and senators will have four hours to question the lawyers for each side, before two hours of debate on whether to allow witnesses, if indeed either party asks to bring witnesses. 

That vote will likely determine if the trial comes to a quick conclusion early-to-mid next week or if it could drag on potentially much longer before a final vote.

Fox News' Kelly Phares, Paul Steinhauser, Mike Emanuel and Chad Pergram contributed to this report.