(CNN) The impeachment drama closing out 2019 and ringing in 2020 is emblematic of a year and political era where the value of truth and fact is being eroded.

The strategy has precluded a debate between the two parties over whether Trump's behavior infringes the values and conduct long expected of Presidents -- since Democrats are working from facts and Republicans frequently simply refuse to recognize incriminating evidence. The President's insistence that his behavior is "perfect" and his tight hold on conservative voters has even deprived GOP lawmakers of a face-saving defense that was once used by Bill Clinton's partisans -- that what he did was unacceptable but not impeachable.

The contest between facts and details and the President's alternative narratives might also offer a 2020 election preview, when Trump is likely to offer an expansive view of a historically successful presidency that might not bear much relation to reality on many points but could prove deeply attractive to voters -- especially thanks to the apparent ongoing strength of the US economy on Trump's watch.

In an age when partisans can find news coverage to suit their facts, it's no surprise that GOP senators have neither the interest nor political space to criticize the President, let alone censure him or kick him out of office.

The end of the Republican institutionalists

One of the most remarkable features of the impeachment saga is how even congressional institutionalists like Senate Majority Leader Mitch McConnell have been willing to cede control of their party to Trump.

Republicans are sticking to a simple strategy to save Trump's presidency that's guided them throughout the impeachment crisis: avoid talking about and unearthing new evidence of his conduct at all costs.

That approach is anchoring the Republican position as Democrats demand more witnesses, documents and transparency in a pre-holidays showdown over the terms of the Senate trial of Trump expected to begin in early January.

McConnell has said he is working closely with the White House counsel on arrangements for the trial -- leading to claims he has ditched a duty to be an independent juror.

The President is also leading the rhetorical charge ahead of the Senate trial.

"Pelosi gives us the most unfair trial in the history of the US Congress, and now she is crying for fairness in the Senate, and breaking all rules while doing so. She lost Congress once, she will do it again!" Trump tweeted Monday

The role of the House of Representatives in impeachment is to investigate and charge a President. Contrary to Trump's claim, the trial is the duty of the Senate alone

With Congress out of town until next year and Trump at his Florida resort, the battle over impeachment degenerated into a series of transcontinental tweets and soundbites.

"President Trump blocked his own witnesses and documents from the House, and from the American people, on phony complaints about the House process. What is his excuse now?" Pelosi asked in a tweet on Monday.

The emerging scenario in the Republican-controlled Senate ahead of the Trump trial mirrors what happened in the Democratic-run House. There, Democrats called witnesses who testified that Trump leaned on Ukraine's President to investigate former Vice President Joe Biden, a 2020 rival, using military aid as well as the prospect of a White House visit as leverage. Republicans spun counter-factual narratives and tried to speak about almost everything but Trump's actions in Ukraine.

The trouble is, new information keeps pouring out. Over the weekend, it emerged that a White House budget official put a freeze on nearly $400 million of military aid to Ukraine within 90 minutes of Trump's call with President Volodymyr Zelensky on July 25.

The revelations emerged in emails released by the Office of Management and Budget in response to a FOIA request by the Center for Public Integrity. They suggested that new details that could damage the President might emerge from new document disclosures during the Senate trial.

But McConnell, stuck in an impasse with his opposite number -- Democratic Minority Leader Chuck Schumer-- over the shape of the trial, is declining to engage, arguing that the Senate is not in the business of making the Democrats' case and that the trial is hardly the place for fresh evidence.

McConnell is far keener to hammer House Speaker Nancy Pelosi for failing to transmit articles of impeachment to the Senate, a course of action apparently meant to bolster Schumer's hand.

"We can't take up a matter we don't have. So hopefully it'll be on the way over at some point," McConnell deadpanned in a news conference with Kentucky reporters on Monday.

Opening a new transparency offensive Monday, Schumer issued a fresh call for documents from the White House, State Department and other agencies.

"There simply is no good reason why evidence that is directly relevant to the conduct at issue in the articles of impeachment should be withheld from the Senate and the American people," Schumer said.

Senate Republicans, Democrats seek to shape the impeachment end-game

The pre-holiday showdown reflects an understanding on both sides about what the next stage of impeachment is really about -- given the certainty that there is no two-thirds majority in the Republican-led chamber to convict Trump of the high crimes and misdemeanors with which he's charged.

It's in the interest of Democrats to leave an impression after the trial that Republicans covered up abuses of power and constitutional chicanery by the President that they can argue to 2020 voters should deprive him of a second term.

"It's hard to imagine a trial not having documents and witnesses," Schumer said Monday. "If it doesn't have documents and witnesses, it's going to appear to the American people that it's a sham trial."

Republicans need to get out of the trial after thwarting such Democratic goals and by sparing the President damage that could backfire on vulnerable swing state Republicans seeking reelection.

McConnell's unwillingness to expand the case reflects the fact that the pattern of evidence unearthed during the impeachment process has not helped the President. If White House officials had information that would clear him of abusing his power over Ukraine, McConnell might be keen to hear from the likes of former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney.

McConnell's arguments have been bolstered, however, by the decision by Democrats not to take court action to challenge Trump's refusal to allow key witnesses to testify.

House Democratic leaders reasoned that such action could take months -- even years -- and argued that the President represented a "clear and present danger" to the Constitution. They instead opted to charge Trump with obstructing Congress in the second article of impeachment.

McConnell seized on that decision on Monday to justify his reluctance to agree to Schumer's demands for witnesses in the Senate trial expected to start early next year.

"What the House could have done is to go to court to try to compel the attendance and they didn't do that," McConnell said on Fox News on Monday.

"They didn't do that. They just blew right through that and accused the president of doing something improper by simply invoking executive privilege which every President has done."