U.S. Senate Majority Leader Mitch McConnell on Tuesday rejected Democratic leader Chuck Schumer’s bid to have key aides to President Donald Trump testify at a Trump impeachment trial in January.

McConnell called the Democrat-controlled House of Representatives’ effort to impeach Trump, likely culminating in a Wednesday vote against the U.S. leader, “slapdash” and “sloppy.” McConnell said it was not the responsibility of the Senate to engage in further fact-finding to “search desperately for ways to get to guilty.”

Schumer says the Senate should hear testimony from four Trump officials, including acting White House chief of staff Mick Mulvaney and former national security adviser John Bolton, about their knowledge of Trump’s monthslong effort to get Ukraine to investigate one of his chief 2020 Democratic challengers, former Vice President Joe Biden. 

Trump’s Ukraine bid came at a time he was temporarily blocking $391 million in military aid that Kyiv wanted to help fight pro-Russian separatists in eastern Ukraine.

But McConnell, who has predicted there is “zero chance” Trump will be convicted in a Senate trial, said that Schumer’s request for more testimony “suggests that even Democrats who do not like this president are beginning to realize how dramatically insufficient the House’s rushed process has been.”

McConnell said having live testimony at a Senate trial would create a “nightmarish precedent” for the Senate. He contended that it is not the role of the Senate to do more fact-finding and investigating, but rather to consider and vote on the two articles of impeachment House Democrats have advanced, accusing Trump of abuse of the power of the presidency related to Ukraine and obstructing Congress in its investigation of his actions.

After McConnell spoke, Schumer told the Senate he does not know what Mulvaney, Bolton, Mulvaney aide Robert Blair and budget official Michael Duffey might say in Senate testimony, suggesting they could have evidence “exculpatory to the president.”

Schumer asked, “What is President Trump afraid of? The truth? A fair trial is one that allows senators all the relevant facts.”

McConnell and Schumer are planning to discuss the parameters of a Senate impeachment trial to try to reach an accord.

But McConnell, with Republicans holding a 53-47 majority in the Senate, could unilaterally set the rules for a trial if at least 51 Republican lawmakers adhere to his apparent wishes for a quick trial with no new testimony, leaving the 100-member Senate to vote on whether to convict Trump and remove him from office after hearing House impeachment managers make their case against Trump and Trump’s White House lawyers defend him.

Schumer, however, could prevail if at least four Republicans side with Democrats to demand more testimony.

The House Rules Committee is meeting Tuesday to decide on rules for Wednesday’s House impeachment debate.  But with Democrats firmly in control of the chamber, Trump’s impeachment appears not to be in doubt, only how many Democrats split from the party-line majority to oppose Trump’s impeachment, and whether any Republicans vote for impeachment.

By Wednesday night, Trump, the 45th U.S. president, could be only the third to be impeached in the country’s 243-year history, even as his conviction at a Senate trial and removal from office remains highly unlikely.

As the House debate nears, politically vulnerable centrist Democratic lawmakers are declaring they will vote to impeach Trump, joining their more liberal colleagues who had long expressed support for trying to remove him from office.

Trump and his supporters had hoped that many of the 31 Democrats elected last year to the House of Representatives from congressional districts won by the president in 2016 would vote against the two articles of impeachment Trump is facing. Some of the lawmakers faced pressure from constituents and opposition TV ads in their districts calling for them to support Trump.  

The half-dozen or so Democratic representatives had been impeachment holdouts. One of the congressmen, Ben McAdams from the western state of Utah, said, “What the president did was wrong. His actions warrant accountability. I will vote yes, knowing full well the Senate will likely acquit the president in a display of partisan theater that Republicans and Democrats perform disturbingly well.”

In the midwestern state of Michigan, Congresswoman Elissa Slotkin, once an analyst for the Central Intelligence Agency, was greeted with both cheers and jeers at a town hall meeting of voters as she defended her decision to vote against Trump.

“I knew it would be controversial either way,” she said. “And I feel very firmly that I’m doing what I think is right. It may be that voters decide in 2020 that they don’t want me as their representative. I hope that’s not the case. I really do.”

One of the articles of impeachment accuses Trump of trying to get Ukrainian President Volodymyr Zelenskiy to launch investigations of Biden, now leading national polls of Democratic presidential candidates,  his son Hunter Biden’s work for a Ukrainian natural gas company, and a debunked theory that Ukraine tried to undermine Trump’s 2016 campaign.

Trump’s Ukraine overtures, including his direct plea to Zelenskiy in a late July call, came as he was temporarily withholding the military aid Kyiv wanted. Trump released the military assistance in September without Zelenskiy undertaking the Biden investigations, proof, Republicans say, that Trump had not engaged in a reciprocal quid pro quo with Ukraine — the military assistance in exchange for the politically tinged Biden investigations.

The second impeachment article accuses Trump of obstructing Congress by refusing to turn over thousands of pages of Ukraine-related documents to House impeachment investigators and blocking key aides from testifying at the weekslong impeachment inquiry.

National polls show a sharply divided electorate on the issue, with about half favoring Trump’s impeachment and removal from office, and half against. But the votes of at least 20 Republicans would be needed to turn against Trump to join a unified Democratic minority bloc to reach the 67-vote threshold for a conviction in the 100-member chamber.

Trump contended in a Tuesday Twitter remark, “Impeachment Poll numbers are starting to drop like a rock now that people are understanding better what this whole Democrat Scam is all about!” 

Impeachment Poll numbers are starting to drop like a rock now that people are understanding better what this whole Democrat Scam is all about!

— Donald J. Trump (@realDonaldTrump) December 17, 2019

He added, “The Stock Market hit another Record High yesterday, number 133 in less than three years as your all time favorite President, and the Radical Left, Do Nothing Democrats, want to impeach me. Don’t worry, I have done nothing wrong. Actually, they have!”

The Stock Market hit another Record High yesterday, number 133 in less than three years as your all time favorite President, and the Radical Left, Do Nothing Democrats, want to impeach me. Don’t worry, I have done nothing wrong. Actually, they have!

— Donald J. Trump (@realDonaldTrump) December 17, 2019

 As the process moved closer to the House vote, House Democrats advancing the case for Trump’s impeachment accused him of “multiple federal crimes,” including bribery and wire fraud, in the abuse of the power of the presidency.

“Although President Trump’s actions need not rise to the level of a criminal violation to justify impeachment, his conduct here was criminal,” House Judiciary Committee Democrats contended. They described Trump’s behavior as “both constitutional and criminal in character,” including bribery and wire fraud. They argued that the president “betrayed the people of this nation” and should be removed from office.

“He has abused his power in soliciting and pressuring a vulnerable foreign nation to corrupt the next United States presidential election by sabotaging a political opponent and endorsing a debunked conspiracy theory promoted by our adversary, Russia,” the report said. “President Trump has done all this for his own personal gain, rather than for any legitimate reason, and has compromised our national security and democratic system in the process. After he was caught, President Trump defiantly insisted his conduct was ‘perfect.'”