A marathon, 12-hour first day in the Senate impeachment trial against President Trump erupted into a shouting match well after midnight Wednesday morning, as Trump's legal team unloaded on Democratic impeachment manager Rep. Jerry Nadler, D-N.Y. -- in an exchange that prompted a bleary-eyed Chief Justice John Roberts to sternly admonish both sides for misconduct in the chamber.

Nadler began the historic spat by speaking in support of the eighth amendment of the day, which was proposed by Senate Minority Leader Chuck Schumer, D-N.Y., just as the clock struck midnight. The proposal would have amended the trial rules offered by Senate Majority Leader Mitch McConnell, R-Ky., to immediately subpoena former National Security Advisor John Bolton.

McConnell's rules, which were eventually adopted in a 53-47 party-line vote at 1:40 a.m. ET Wednesday and largely mirror those from the Bill Clinton impeachment trial in 1999, permit new witnesses and documents to be considered only later on in the proceedings, after opening arguments are made.

But Nadler, who was overheard apparently planning to impeach Trump back in 2018, said it would be a "treacherous vote" and a "cover-up" for Republicans to reject the Bolton subpoena amendment, claiming that "only guilty people try to hide evidence." Bolton has reportedly described Trump's conduct as akin to a "drug deal," and he has indicated he would be willing to testify and provide relevant information.

“It’s embarrassing,” Nadler began. “The president is on trial in the Senate, but the Senate is on trial in the eyes of the American people. Will you vote to allow all the relevant evidence to be presented here? Or will you betray your pledge to be an impartial juror? ... Will you bring Ambassador Bolton here? Will you permit us to present you with the entire record of the president's misconduct? Or will you instead choose to be complicit in the president's coverup? So far I'm sad to say I see a lot of senators voting for a coverup, voting to deny witnesses, an absolutely indefensible vote, obviously a treacherous vote.”

Trump's legal team, which has argued that Democrats' impeachment case couldn't be as "open-and-shut" as advertised given the apparently urgent need for new evidence even after the House impeachment inquiry, immediately rose in response.

"We've been respectful of the Senate," an animated White House counsel Pat Cipollone fired back. "We've made our arguments to you. And you don't deserve, and we don't deserve, what just happened. Mr. Nadler came up here and made false allegations against our team. He made false allegations against all of you; he accused you of a cover-up. He's been making false allegations against the president. The only one who should be embarrassed, Mr. Nadler is you, for the way you've addressed the United States Senate. This is the United States Senate. You're not in charge here. ... It’s about time we bring this power trip in for a landing."

Then, Trump attorney Jay Sekulow hammed Nadler for suggesting that executive privilege, a longstanding constitutional principle protecting executive branch deliberations from disclosure, wasn't legitimate. The White House has said the privilege prevents Democrats from forcing administration officials to provide testimony before Congress.

"At about 12:10 a.m., January 22, the chairman of the [House] Judiciary Committee, in this body, on the floor of this Senate, said 'executive privilege and other nonsense,'" Sekulow said. "Now think about that for a moment. 'Executive privilege and other nonsense.' Mr. Nadler, it is not 'nonsense.' These are privileges recognized by the Supreme Court of the United States. And to shred the Constitution, on the floor of the Senate. To serve what purpose? The Senate is not on trial. The Constitution doesn't allow what just took place. Look what we've dealt with for the last, now 13 hours. And we hopefully are closing the proceedings, but not on a very high note."

Sekulow accused Democrats of hypocrisy given that Attorney General Eric Holder had similarly cited executive privilege to avoid providing documents as part of House Republicans' "Fast and Furious" gunrunning probe. Holder was later held in contempt of Congress. Additionally, Sekulow argued that House Democrats should have gone to court if they wanted to enforce their subpoenas, rather than rush to a Senate trial and then complain about the issue.

"'Only guilty people try to hide evidence?'" Sekulow asked, quoting Nadler incredulously. "So, I guess when President Obama instructed his attorney general to not give information, he was guilty of a crime? That's the way it works, Mr. Nadler? Is that the way you view the United States Constitution? Because that's not the way it was written, that is not the way it's interpreted, and that's not the way the American people should have to live."

The outbursts prompted Roberts, who as Chief Justice of the United States is constitutionally required to serve as the presiding judge in the impeachment trial, to issue a highly unusual rebuke to both sides of the debate.

"It is appropriate at this point for me to admonish both the House managers and the president's counsel in equal terms to remember that they are addressing the world's greatest deliberative body," Roberts said. "One reason it has earned that title is because its members avoid speaking in a manner, and using language, that is not conducive to civil discourse. "

Roberts continued: "In the 1905 [Judge Charles] Swayne trial, a senator objected when one of the managers used the word 'pettifogging' -- and the presiding officer said the word ought not to have been used. I don't think we need to aspire to that high a standard, but I do think those addressing the Senate should remember where they are."

The vote on the Bolton amendment, like the roll call on Schumer's previous failed quixotic proposals on the day, was not a final determination on any witness or document request, because McConnell's proposal would allow new evidence to be considered later on in the process.

At 1:30 a.m. ET, Schumer introduced his last amendment to McConnell's rules-- and he unexpectedly put Roberts back in the spotlight. The proposal would have allowed Roberts to decide the appropriateness of witnesses, which Republicans nixed because the Constitution affords the Senate the "sole" power over impeachment trials.

That last amendment was tabled by a 53-47 party-line vote, just like ten of Schumer's other proposals.

When McConnell thanked Roberts for his "patience" as the proceedings wrapped up at 1:40 a.m. ET following that vote, Roberts remarked to applause, "It comes with the job." The trial adjourned until 1 p.m. ET on Wednesday.

As some Democratic impeachment managers told Fox News that they were exhausted from the "long day" while staffers streamed out of the Capitol complex at 2 a.m. ET, McConnell smirked and simply told Fox News that it had been a "good day."

McConnell's rules package

Under McConnell's final, adopted rules resolution, both the Democrats' impeachment managers and Trump's lawyers will now have three session days, totaling 24 hours, allocated to present their case.

McConnell's original resolution had allowed 24 hours of arguments over only two days. Democrats complained that that would push the trial into “the dead of night,” and McConnell expanded the timeline with a handwritten note on the resolution on Tuesday after the GOP moderates voiced similar concerns.

A spokeswoman for Maine Republican Sen. Susan Collins said that she and others had raised concerns. Collins saw the changes as significant improvements, the spokeswoman said. Additionally, Ohio GOP Sen. Rob Portman and a substantial number of other Republicans from across the party's ideological spectrum reportedly wanted to make the changes.

The rules for Clinton’s trial give the two sides 24 hours each for arguments but didn't specify how many days. They each took three.

The rules for senators’ questions are identical as compared with the Clinton trial: “Upon the conclusion of the president’s presentation, senators may question the parties for a period of time not to exceed 16 hours." Per underlying Senate rules, upon which both resolutions were based, the senators have to submit those questions in writing.

After the senators' question period, Trump’s trial will follow Clinton’s format with debate over witnesses. In the Trump trial, the House prosecutors and White House defense will have four hours of debate over the question of whether to subpoena witnesses or documents.

The Clinton resolution was similar, but it gave the two sides six hours of debate. Both sets of rules also require witnesses to be deposed before they testify publicly.

In Clinton’s trial, the Senate eventually decided to depose three witnesses and allow video excerpts to be played on the Senate floor. But the public had already heard from all three of those witnesses, as they had been interviewed by Starr’s team.

It’s still unclear what will happen with witnesses in Trump’s trial.

The Clinton rules resolution provided that there would be a vote on a motion to dismiss the charges. McConnell’s resolution does not mention a motion to dismiss, known as a "kill switch" in GOP circles, but does not rule it out.

Trump has tweeted that he would like such a motion, but Senate Republicans have indicated that they don’t have the votes to pass it and that they would prefer for the president to be acquitted, as he is expected to be. Still, any senator could offer a motion to dismiss the two articles.

Republicans unite, vote after vote

With the rules debate resolved, all indications are that the days ahead are likely to be acrimonious. Shortly before the trial dragged on overnight into the wee hours Wednesday with a series of Democrat-proposed subpoena requests that Republicans methodically shot down one-by-one, McConnell had offered Democrats an option: bundle all of their document requests into a "stack" for a single vote, so that the process could move along.

But, Schumer was having none of it -- and made clear that he wanted individual votes on each of Democrats' proposed amendments to McConnell's trial rules, no matter how long it took.

"A number" of additional amendments were going to be offered, Schumer promised. Indeed, at 10:30 p.m. ET, Schumer rose to present his sixth proposal of the day: a subpoena for the testimony of White House budget aides Robert Blair and Michael Duffey. Debate on that proposal wrapped up in a little over an hour before the Senate voted to table it.

Then, at 11:19 p.m. ET, Schumer introduced yet another amendment, in the form of a procedural modification requiring that if any party "seeks to admit evidence that has not been submitted as part of the record of the House of Representatives and that was subject to a duly authorized subpoena," then that party "shall also provide the opposing party all other documents responsive to that subpoena." However, Trump's lawyers objected to the premise that the House's subpoenas were "duly authorized," given that the subpoenas were not issued pursuant to an impeachment inquiry authorized by a vote of the full House.

The Bolton amendment came next, followed by another procedural amendment on subpoenas.

In all, the Senate handed President Trump a series of wins throughout the day Tuesday by voting 53-47 ten separate times to effectively kill a series of previous proposals from Schumer to subpoena White House, State Department, Defense Department, and Office of Management and Budget documents, as well as testimony from acting White House Chief of Staff Mike Mulvaney, Blair and Duffey, respectively.

The party-line votes demonstrated GOP unity at the start of the trial, which is all but certain to result in the president's acquittal.

"I do think those addressing the Senate should remember where they are." — Chief Justice John Roberts, after midnight

An additional, less consequential amendment on written responses was tabled by a 52-vote majority. Collins joined with Democrats on that vote, marking the first time a Republican did so all day.

In a worrying sign for Democratic impeachment managers, there were signs that attention was flagging in the chamber with the night winding on. As of 10 p.m. ET, the galleries to watch the proceedings contained only 29 members of the public, many of them with eyes glazed.

Idaho GOP Sen. James Risch could even be seen apparently sleeping at around 5:30 p.m. ET, and other senators appeared bored. The fatigue seemingly risked frustrating senators as Democrats tried to make their case, while also prolonging the proceedings with futile amendments.

"It’s getting late," White House counsel Pat Cipollone said late Tuesday night. "I would ask you, respectfully, if we could simply start, maybe tomorrow we can start -- and they can make their argument, and they can, I guess, make a case that they once called 'overwhelming.' We'll see... Seriously, can we please start?”

OOPS? BIDEN TEAM TOUTS UKRAINE ACTIVIST WHO CALLED HUNTER BIDEN'S ACTIONS 'VERY BAD'

Meanwhile, a report emerged in Politico that Democrats' lead impeachment manager, California Rep. Adam Schiff, may have publicly mischaracterized evidence in the case. Schiff had asserted that Rudy Giuliani associate Lev Parnas “continued to try to arrange a meeting with President [Volodymyr] Zelensky" -- but the "mr Z" that Parnas was referring to in his text message was apparently not Ukraine's president, but Ukrainian businessman Mykola Zlochevsky.

Separately, as Democrats' amendments were being summarily shot down, reports emerged that some Democrats were privately considering something of a compromise: calling for the testimony of Hunter Biden in exchange for the appearance of some key administration officials. Biden obtained a lucrative board role with a Ukrainian company while his father, Joe Biden, was overseeing Ukrainian policy as vice president.

Trump had asked in his now-infamous July 25 call with Ukraine's president for a look into Joe Biden's admitted pressure campaign to have Ukraine's top prosecutor fired.

Republicans have sought to portray Trump's push for a probe as a legitimate request given the Bidens' dealings in Ukraine, while Democrats have alleged that senior administration officials would testify that the administration withheld military aid to Ukraine in order to secure a politically motivated probe. Mulvaney, for example, has publicly argued that there is nothing wrong with tying financial assistance to anti-corruption efforts and other U.S. objectives, even as the administration has denied specifically targeting the Bidens for political purposes.

A moment of levity

The barrage of amendments Tuesday night killed early hopes that the senators would have time to meet in a closed session to converse -- which would be a valuable opportunity, given that the senators were legally barred from having any sustenance other than water or milk at their desk all day, and could not communicate verbally with one another during the proceedings.

The restriction on cellphone possession and oral interaction led some members to pass and flash written notes to each other like students in a classroom, as Democratic House impeachment managers and the president's legal team traded lengthy legalistic arguments.

At one point during the proceedings, former Bill Clinton press secretary and CNN political analyst Joe Lockhart wrote on Twitter that Texas GOP Sen. Ted Cruz could go to "prison," noting that Cruz's Twitter account was posting tweets during the trial. Lockhart was quickly mocked by social media users pointing out that it's common for senators' Twitter accounts to be run by staff, and Cruz's representatives confirmed to Fox News that Cruz had not sneaked his phone into the chamber.

TRUMP'S LEGAL TEAM GOES ON THE OFFENSIVE

Even Cruz's staff couldn't resist poking some fun at Lockhart, writing "COME AND TAKE IT," with an image of a cellphone.

It was a moment of levity in an otherwise emotionally charged day, with Democrats accusing the president of "high crimes and misdemeanors" and Republicans calling out what they see as a transparent partisan stunt.

"It's a partisan impeachment they've delivered to your doorstep in an election year," Cipollone thundered early in the day, pointing out that Sens. Elizabeth Warren and Bernie Sanders, and others, were being pulled off the campaign trail. "Some of you should be in Iowa."

"They're not here to steal one election, they're here to steal two elections," Cipollone added.

JIM JORDAN: THE FOUR FACTS DEMS CAN'T CHANGE

Trump attorney Patrick Philbin said Democrats' document requests were a "stunning admission" that House prosecutors, who had full rein to conduct their own impeachment inquiry, were now essentially asking the Senate "to do their job for them."

California Democratic Rep. Zoe Lofgren, one of the House Democrats' impeachment managers, countered in her remarks on the Senate floor that additional documents were needed to provide "clarity."

“As powerful as our evidence is," Lofgren said, "we did not receive a single document from an executive branch agency including the White House itself."

Lofgren specifically sought, among other materials, summary notes from an Aug. 30, 2019 meeting between Trump, Defense Secretary Mark Esper and Secretary of State Mike Pompeo in which they apparently tried to convince the president that freeing up aid money for Ukraine would be "the right thing to do."

“It would be wrong for you senators ... to be deprived of the relevant evidence,” Lofgren said.

IMPEACHMENT TRIAL RULES SEEM WRITTEN IN THE WHITE HOUSE, NOT THE SENATE, SCHUMER SAYS

For his part, Trump appeared undeterred by the proceedings, and committed to conducting business as usual.

“READ THE TRANSCRIPTS!” the president tweeted from overseas, as he returned to his hotel far away from Washington's impeachment drama, at a global leaders economic conference in Davos, Switzerland.

As the contentious day wrapped up in Washington well after midnight, Trump posted another high-spirited tweet from Davos that again pointedly avoided commenting on the trial.

"Making great progress in @Davos," Trump wrote. "Tremendous numbers of companies will be coming, or returning, to the USA. Hottest Economy! JOBS, JOBS, JOBS!"

Fox News' Chad Pergram, Mike Emanuel, Caroline McKee, Jason Donner, and Adam Shaw contributed to this report, as well as The Associated Press.