Mitch McConnell threatened on Thursday to cancel Donald Trump's impeachment trial in the Senate if 'scared' Nancy Pelosi refuses to send him the formal articles of impeachment that Democrats passed Wednesday night.

The Speaker of the House and the Senate Majority leader went to war over next steps in the impeachment process, with Pelosi slamming McConnell as a 'rogue leader'⁠—and he blasted her indictment of the president as 'slapdash' and 'unfair.'

The dispute exploded into the open the morning after Democrats voted to impeach Trump, with the president bragging he could prevaIl by 'default.'

'If the Do Nothing Democrats decide, in their great wisdom, not to show up, they would lose by Default!,' Trump argued on Twitter of his upcoming Senate trial, which is now in doubt.

Pelosi has to transmit the articles of impeachment and appoint 'managers' to prosecute the president. She offered no timeline, saying she wanted to see the Senate's plan for a 'fair trial,' effectively holding the articles over McConnell's and Trump's heads.

McConnell, who previously said he wanted to hold a trial in January, responded: 'It's beyond me how the Speaker and Democratic Leader in the Senate think withholding the articles of impeachment and not sending them over gives them leverage.'

'Frankly, I'm not anxious to have the trial. If she thinks her case is so weak she doesn't want to send it over, throw me into that briar patch.'

Meanwhile, Trump's lawyers are exploring the legal question of whether or not Trump has even been impeached since Pelosi hasn't sent over the articles, Bloomberg News reported.

They argue, based on how the impeachment process is laid out in the Constitution, an impeachment isn’t formalized until the House reports the charges to the Senate.

Open warfare: Nancy Pelosi slammed Mitch McConnell as a 'rogue leader' and he called her articles of impeachment 'slapdash' and 'unfair' as the two clashed over the Senate trial of Donald Trump

Senate Majority Leader Mitch McConnell claimed in a floor speech that House Speaker Nancy Pelosi is afraid to send him the articles of impeachment that House Democrats passed Wednesday night

'Lawyers close to Trump are exploring whether Pelosi’s decision to temporarily withhold articles of impeachment from the Senate could mean that the president hasn’t actually been impeached. The case is largely rhetorical, but could provide WH and Senate Republicans leverage,' Bloomberg reported.

Bill Clinton and Andrew Johnson are both labeled as 'impeached' even though neither president was convicted in their respective Senate trials.

The legal and historic argument was a president is impeached when the House approves articles of impeachment. But the additional element of the transfer of the articles to the Senate adds a legal question that could require a court answer if the articles aren't transmitted soon.

Meanwhile, McConnell and the president both blasted Pelosi for refusing to move to the next step, with Trump unleashing a storm of tweets and retweets and venting: 'PRESIDENTIAL HARASSMENT.'

The president also charged Democrats with being 'ashamed' of the impeachment articles.

'They don't want to put them in because they're ashamed of them,' he said Thursday in the Oval Office.

McConnell also criticized Democrats on the Senate floor, accusing them of creating what he called an 'unfair, unfinished product'— charges that stemmed from 'partisan rage.'

Calling Pelosi's work 'constitutionally incoherent,' he said impeaching a president on the basis of political disagreements would 'invite an endless parade of impeachable trials' in the future, making House leaders 'free to toss up a jump-ball every time they feel angry.'

'She's failed the country,' McConnell said.

'It was like the speaker called up Chairman [Jerrold] Nadler and ordered up "One impeachment, rushed delivery, please".'

Chuck Schumer, the Democratic Senate minority leader accused McConnell of offering no defense of Trump's actions

President Donald Trump held a rally as House Democrats were passing the articles, sticking to his guns and mocking them

Pelosi herself held a press conference after McConnell spoke and offered no hint on when she would move.

'Just to get this off the table right away, we impeached the president immediately and everybody was on to the next thing,' she said.

'The next thing will be when we see the process that is set forth in the Senate. Then we'll know the number of managers that we may have to go forward and who we would choose.'

And she grew testy as reporters pressed her for more details on when the two articles of impeachment will end up on McConnell's desk.

'I'm not going to answer anymore questions on this. Clearly you understand when we see what their process is we will know who and how many we want to send over, not until then. I'm not going to go there anymore,' Pelosi said.

Our founders, when they wrote the constitution, they suspected that there could be a rogue president. I don't think they suspected that we could have a rogue president and a rogue leader in the Senate at the same time. Nancy Pelosi

But she did react angrily to McConnell's speech, saying: 'I saw some - I didn't see it - but heard some of what Mitch McMconnell said today and it reminded me that our founders, when they wrote the constitution, they suspected that there could be a rogue president.

' I don't think they suspected that we could have a rogue president and a rogue leader in the Senate at the same time.'

In the Senate, McConnell declared that 'their slapdash process has concluded in the first purely partisan presidential impeachment since the wake of the Civil War.'

Citing previous House votes that fell short of authorizing impeachment inquiries, he said Democrats had 'tried to impeach President Trump for being impolite to the press, for being mean to professional athletes, for changing President Obama's policy on transgender people in the military.'

'All of these things were high crimes and misdemeanors according to the Democrats,' he said.

McConnell cited Democrats' earlier pledges to impeach Trump as proof that Wednesday's vote 'was not some neutral judgment that Democrats came to with great reluctance. It was the predetermined end of a partisan crusade that began before President Trump was even nominated, let alone sworn in.'

House Democrats have begun pressing Pelosi to force the Senate to tailor the upcoming constitutional trial to their wishes—by refusing to send the articles of impeachment to McConnell until he agrees to their terms.

Frankly, I'm not anxious to have the trial. If she thinks her case is so weak she doesn't want to send it over, throw me into that briar patch Mitch McConnell

McConnell called her bluff, saying she's afraid to hand him the baton because she knows the articles are weak.

'Pelosi suggested that House Democrats may be too afraid to even transmit their shoddy work product to the Senate,' he will say, mocking her suggestion in a post-vote press conference that she'll hold the two articles over his head until he agrees to a 'fair' trial.

In response Chuck Schumer, the Democratic Senate minority leader accused McConnell of offering no defense of Trump's actions.

He renewed his call for witnesses at the trial saying: 'Is the president's case so weak that none of the President's men can defend him under oath?'

And echoing McConnell's criticism of 'the most rushed, least thorough, and most unfair impeachment inquiry in modern history,' Schumer said the Republicans were 'plotting the most rushed, least thorough, and most unfair impeachment trial.

A defiant Trump partially quoted the Senate's rules for impeaching President Andrew Johnson in 1868, saying in a tweet that '[t]he Senate shall set the time and place of the trial.'

'The Do Nothing Party want to Do Nothing with the Articles & not deliver them to the Senate, but it's Senate's call!' he warned, saying they would 'lose by default' if they decided to ignore whatever schedule McConnell sets.

'PRESIDENTIAL HARASSMENT!' Trump tweeted in a standalone message.

Schumer this week demanded McConnell agree to swear in a list of trial witnesses that include senior Trump administration officials and Trump's personal lawyer Rudy Giuliani, people who House Democrats decided not to subpoena during their impeachment inquiry.

McConnell said Schumer has been 'searching for ways the Senate could step out of our proper role and try to fix House Democrats' failures for them.'

George Washington is said to have told Thomas Jefferson that the U.S. Senate was designed to be a calming counterpoint to the more raucous House of Representatives, in the way a teacup's saucer 'cools' a hot beverage.

McConnell, famous for embracing a plodding style when key legislation is on his desk, leaned on the oft-quoted 'cooling saucer of democracy'—saying that the U.S. Constitution's framers 'built the Senate to provide stability' and '[t]o keep partisan passions from boiling over. Moments like this are why the United States Senate exists.'

Pelosi told reporters after adjourning the House of Representatives on Wednesday night that she's in no hurry to send the two articles of impeachment to McConnell for a trial. Her caucus passed them without any Republican votes, accusing Trump of abusing his power and showing open contempt for Democrats' investigation by blocking witnesses and document demands.

The Articles of Impeachment were approved Wednesday night with no Republican votes; Rep. Tulsi Gabbard voted 'present' instead of 'yes,' and two other Democrats bucked Pelosi to openly side with the GOP

The Republican-led Senate owns the next chapter of the saga, a trial where Chief Justice John Roberts will preside. An unlikely two-thirds supermajority is required to convict the president and remove him from office.

McConnell, a Kentucky Republican, expects his Republican majority to exonerate Trump. But that can't happen until impeachment 'managers,' duos chosen by both parties, present the Senate with the twin impeachment articles.

Pelosi said Wednesday night that she won't be ready to let go of the process until McConnell demonstrates the trial will be 'fair'—and she's nowhere near convinced yet.

The Washington Post quoted Oregon Democratic Rep. Earl Blumenauer overnight saying he has talked to three dozen Democratic lawmakers who favor 'rounding out the record and spending the time to do this right.'

'At a minimum, there ought to be an agreement about access to witnesses, rules of the game, timing,' Blumenauer said of the upcoming Senate trial.

And an unnamed Democrat told the newspaper that Democrats are discussing 'serious concern about whether there will be a fair trial on the Senate side.'

Impeachment managers are appointed via House resolutions; Thursday is the last day the House will be in session until January 7.

Trump vented about his political plight at a political rally in Michigan while House Democrats were voting to impeach him in Washington

'We have legislation approved by the Rules Committee that will enable us to decide how we send over the articles of impeachment,' Pelosi said. 'We cannot name managers until we see what the process is on the Senate side.'

'So far we haven't seen anything that looks fair to us,' she warned. 'So hopefully it will be fairer. And when see what that is, we'll send our managers.'

'Let me tell you what I don't consider a fair trial,' Pelosi said as she read from a piece of paper an aide handed her.

'This is what I don't consider a fair trial, that Leader McConnell has stated that he's not an impartial juror, that he's going to take his 'cues' from the White House, and he is working in total coordination with the White House counsel's office.'

READ THE ARTICLES OF IMPEACHMENT AGAINST DONALD TRUMP In 1,414 words, the articles of impeachment passed by the House of Representatives Wednesday lay out two charges against President Donald Trump. Article I: Abuse of Power Using the powers of his high office, President Trump solicited the interference of a foreign government, Ukraine, in the 2020 United States Presidential election. Accused: Donald Trump has two articles of impeachment against him He did so through a scheme or course of conduct that included soliciting the Government of Ukraine to publicly announce investigations that would benefit his reelection, harm the election prospects of a political opponent, and influence the 2020 United States Presidential election to his advantage. President Trump also sought to pressure the Government of Ukraine to take these steps by conditioning official United States Government acts of significant value to Ukraine on its public announcement of the investigations. President Trump engaged in this scheme or course of conduct for corrupt purposes in pursuit of personal political benefit. In so doing, President Trump used the powers of the Presidency in a manner that compromised the national security of the United States and undermined the integrity of the United States democratic process.' Article II: Obstruction of Congress As part of this impeachment inquiry, the Committees undertaking the investigation served subpoenas seeking documents and testimony deemed vital to the inquiry from various Executive Branch agencies and offices, and current and former officials. In response, without lawful cause or excuse, President Trump directed Executive Branch agencies, offices, and officials not to comply with those subpoenas. President Trump thus interposed the powers of the Presidency against the lawful subpoenas of the House of Representatives, and assumed to himself functions and judgments necessary to the exercise of the 'sole Power of Impeachment' vested by the Constitution in the House of Representatives. In the history of the Republic, no President has ever ordered the complete defiance of an impeachment inquiry or sought to obstruct and impede so comprehensively the ability of the House of Representatives to investigate 'high Crimes and Misdemeanors.'' This abuse of office served to cover up the President's own repeated misconduct and to seize and control the power of impeachment -- and thus to nullify a vital constitutional safeguard vested solely in the House of Representatives. Advertisement

In Michigan, a sweat-glowing Trump said during a raucous campaign rally that he expects no drama.

'The Republican Party has never been so affronted, but they've never been so united as they are right now, ever. Never,' the president said.

'And I know the senators and they're great guys. And women too. We have some great women, we have great guys, they're great people. They love this counry. They're going to do the right thing.'

'Americans will show up by the tens of millions next year to vote Pelosi the hell out of office,' Trump boasted, calling for the restoration of a Republican House majority.

On the eve of the House impeachment vote, a few thousand protestors carried signs and marched from Times Square to Union Square in New York City

In theory Pelosi could sit on the paperwork indefinitely, leaving Trump in constitutional purgatory while blaming Senate Republicans for dooming the process with partisanship.

In the meantime, Senate Minority Leader Chuck Schumer is pressing McConnell for permission to call a list of witnesses who Democrats want to hear from.

House Democrats denied Republicans the ability to call witnesses of their choice in Intelligence and Judiciary Committee hearings during the impeachment process.

Pelosi's gambit could be resolved once Schumer has exhausted his leverage.

'We have done what we set out to do,' she said, adding that 'right now, the president is impeached.'

'We'll see what happens over there.'