Washington (CNN) It might have been the day when Donald Trump's Washington finally slipped the limits of credulity.

The administration's big guns -- Attorney General William Barr, Secretary of State Mike Pompeo and Treasury Secretary Steven Mnuchin -- got a hostile reception on Capitol Hill from Democrats eager to pull back a presidency they see as out of control.

Tuesday zipped by in a blur of grave constitutional tussles scented with the whiff of corruption. Surreal exchanges unfolded in Congress that left witnesses spluttering. There were superficial feuds over alternative facts.

The bizarre sideshow encompassed climate denial, a spat about Adolf Hitler, one senator's meditation on Hollywood's molesting actors and a schoolroom-style squabble between a top Democrat and Mnuchin.

The weird juxtaposition of the weighty and the frivolous seemed an apt metaphor for how Trump's presidency has torn age-old codes of political custom and behavior to shreds.

In the odd new normal of the Trump era, several top Cabinet officials found themselves answering questions about topics that would have seemed unthinkable in more conventional times.

Barr faced a grilling over his conclusions about the most serious investigation into presidential conduct in years -- and a report by special counsel Robert Mueller that Americans have yet to read.

Mnuchin was beating back demands for the release of Trump's tax returns, after the President bucked tradition and refused to share them with Americans.

Both men left serious questions unanswered that offered ample evidence of the Trump administration's allergy to scrutiny, which is knotting up the political system.

Their intransigence offered a reminder that while Democrats in the House now have the duty of oversight after the midterm elections, making effective use of their power is far from easy.

For once, the President himself was not in the brightest spotlight.

More than anything, though, a day of barely suppressed tensions, flaring mistrust and a disconnect between foes who barely share a common political language exemplified the effect the 45th President has had on the culture and character of Washington.

The Russia scandal roars back

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The capital is still reverberating after the forced resignation of Homeland Security Secretary Kirstjen Nielsen on Sunday, in a White House purge of her agency amid an immigration crisis.

But the Russia scandal, which dominated politics for two years before a brief hiatus when Mueller ended his probe last month, came roaring back.

Barr sparked new intrigue when he refused to say whether the White House has seen, or will see, the full Mueller report ahead of the release of a redacted version he promised to release within in a week.

His reticence only fanned Democratic suspicions that the newly installed attorney general is running interference for Trump -- after Barr released a letter last month underlining what he says are bottom-line findings that are largely favorable to the President.

Such misgivings will hardly be eased by Barr's testimony that Mueller had been given the chance to review the letter before it went out but had declined.

Reports last week said members of Mueller's team had been dismayed, feeling that Barr inadequately portrayed the findings of a probe they thought was more damaging to Trump than he suggested.

Furious Democrats accused Barr of covering up for his new boss.

"It's what he was hired to do, which is to protect the President," said House Intelligence Chairman Adam Schiff.

"The President wanted his own Roy Cohn and apparently he got one," the California Democrat said, comparing Barr to the New York attorney and Machiavelli who had mentored Trump as a rising real estate kingpin.

House Minority Leader Kevin McCarthy of California, until recently part of a GOP majority that spent months trying to make public documents embarrassing to Democrats, argued against Congress exercising oversight over the unredacted report.

"Do you think they would keep a secret? No. We would harm people," he said.

The kind of chaos now unfolding in Washington -- with American set against American and skepticism rife about the legitimacy of the President -- is the kind of result of which Putin can only have dreamed at the start of the Russian election interference effort.

It may not be a coincidence that he chose this moment to offer his most expansive remarks yet on the Mueller probe, which appear calculated to sow even more discord.

Choosing talking points similar to Trump's own, Putin said in St. Petersburg that the scandal was "total nonsense aimed only at a domestic audience."

"It's clearer to Trump what a witch hunt is. We know the history of the United States. It's a dark page in American history," Putin said of the investigation.

Like Barr, Mnuchin left his Democratic inquisitors with the impression that the White House was stacking the deck behind the scenes.

He revealed that his department's lawyers had consulted with the White House before Democrats lodged their request with the IRS for six years of the President's tax returns last week.

Given that the legal process underlying the request is supposed to be insulated from the White House to avoid interference, his answer set alarm bells ringing again.

"I don't see that as interference," Mnuchin said, arguing that his team had not taken direction from White House lawyers.

Even the lighter moments on Tuesday emphasized the feeling of giant disconnect that pervades Washington.

Democratic Rep. Mike Quigley of Illinois opened the hearing by asking Mnuchin how his NCAA bracket had panned out.

"I'm a bigger fan of professional basketball," Mnuchin replied.

Festering ill feeling between the administration and Democrats boiled over when Mnuchin sought to leave a later hearing for an appointment with a senior official from Bahrain.

After an exchange that sounded like bickering between a teacher and a challenging student, Mnuchin told House Financial Services Chair Maxine Waters that he needed to be formally dismissed: "You're supposed to take the gavel and bang it, that's the appropriate ..."

The California Democrat replied: "Please do not instruct me as to how I am to conduct this committee."

'Are you serious?'

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Tuesday's most flagrant display of failing to connect came over at the House Oversight Committee, where two old Washington bulls -- John Kerry and Chuck Hagel -- testified on climate change.

Republicans on the panel greeted Kerry like a returning victim ready for another roughing up in a hearing that revealed two rival sides working from a contradictory vision of fact.

The former secretary of state had trouble believing the assaults mounted by GOP members on the subject of global warming.

At one point, Kentucky's Republican Rep. Thomas Massie questioned Kerry on his Yale degree, suggesting that someone who had majored in political science was unqualified to testify on climate change.

"I think it's appropriate that someone with a pseudo-science degree is here pushing pseudo-science in front of our committee today," Massie said.

A baffled Kerry replied: "Are you serious?"

After another exchange, in which Massie downplayed the impact of humans on climate change, Kerry shot back, saying this was "just not a serious conversation."

"Your testimony is not serious," Massie replied.

In a more sinister sign of the times, YouTube was forced to disable comments on a livestream of a House Judiciary Committee hearing on hate crimes after it was flooded with racist and anti-Semitic remarks.

In a contentious moment inside the hearing room, Rep. Ted Lieu held up his cell phone to play earlier comments made by a witness that he suggested legitimized Hitler and played into white nationalist sentiment.

The witness, Candace Owens, of the conservative group Turning Point USA, who had subsequently distanced herself from the remarks, hit back angrily at the California Democrat.

"I think it's pretty apparent that Mr. Lieu believes that black people are stupid and will not pursue the clip in its full entirety," she said.

Owens accused Lieu of taking her remarks out of context, but the exchange was a reminder that it is never a good idea to include Hitler in any contemporary political analogy.

In an equally strange twist on another difficult issue, Sen. John Kennedy offered a typically florid aside in a floor speech touting his bill on tackling sexual harassment.

"I don't know how the actors in Hollywood have time to make movies," said the Louisiana Republican. "They are too busy molesting each other."

In the Senate Foreign Relations Committee, it was a case of poacher-turned-gamekeeper as Pompeo turned up to testify.

Pompeo, in a previous incarnation as a Kansas congressman, was a master of committee histrionics, especially when Hillary Clinton was in the witness chair.

Now that he's taken her place, he's disdainful of such behavior, and there were tense exchanges on US policy in the Middle East and Trump's scything of the diplomatic budget, which Sen. Chris Murphy, a Connecticut Democrat, blasted as "bananas."

But finally, at the end of a long, dispiriting Washington day, there was a rare moment of comity, after Sen. Chris Coons, a Delaware Democrat, offered a survey of foreign policy challenges in Africa.

"I think I agree with everything you said there," Pompeo said.