Maybe they should just change the name of Trump Tower to Russia House. And place a plaque in the room on the 25th floor where the Axis of Moral Blindness of Donald Trump Jr, Jared Kushner and Paul Manafort met in June 2016 with a Russian attorney in hopes of getting the Kremlin’s help in bringing down Hillary Clinton.

What was stunning about Trump Jr’s Fox News interview with Sean Hannity Tuesday night was the fast-talking self-confidence of the president’s oldest son. It was as if Trump Jr had entered the No Embarrassment Zone.

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While he conceded a twinge of retrospective regret, even now Trump Jr failed to radiate any sign that he understands that presidential campaigns do not go trolling for opposition research from hostile foreign powers. “It’s what we do in business,” he said with innocence of Little Bo Peep. “If there is information out there, you want it.”

By his own admission, Trump Jr pressed the Russian attorney to dish the dirt. It was a different era, the president’s son stressed, since it was “pre-Russia mania”. It was as if the nature of Vladimir Putin’s regime had changed overnight from Jeffersonian democracy to thuggish authoritarianism.

Trump Jr probably believes his own talking points, a trait that he has inherited from his father. Without pre-judging the investigation by Robert Mueller, it is a fair assessment that if political stupidity were an indictable offence, Trump Jr would be facing a lengthy sentence.

The leaders of the Republican party, however, cannot claim similar ignorance about the nature of the Trump regime. The Republican’s paralysis involves more than the party’s collective 2016 decision to put its integrity in a locked vault in Mar-a-Lago.

Aided by cheerleaders like Hannity, Donald Trump’s support among Republicans continues to hold firm at levels above 80%. But the same bitter mood that elected Trump has left Republicans in Congress vulnerable to voter retribution, as internal polls for 2018 candidates often tilt in alarming directions.

Thus the Trump version of Catch-22: the more that Republicans in Congress become skittish about their own political futures, the more they are wedded to the guttersnipe president and his bumbling family. Even as the tumult in the White House jeopardizes the Republican’s ability to govern, these Republican incumbents lack the courage to defy Trump’s base.

“How does it end?” That was the question I kept hearing all day in Washington. If there is to be a satisfying answer (from a constrained, impotent president ranting at the TV set to, yes, impeachment), it depends on enough Republican incumbents deciding that their reputations, their historical legacy and the future of their party are more important than short-term political calculus.

Enough with the furrowed brows and expressions of “deep concern”. A single prominent Republican in Congress saying flatly: “This is unconscionable and forever unsupportable” is more important than 873 liberal law professors chattering about “a textbook case of collusion” and “obstruction of justice”.

In a sense, the Republicans fit Colin Powell’s Pottery Barn rule about Iraq: “You break it, you own it.” Republican leaders, from Paul Ryan to Reince Priebus, allowed Trump to break the Republican party and now they own the consequences.

Where have you gone, Howard Baker? Our nation lifts its lonely eyes to you.

Baker, who died in 2014, was the senior Republican on the Senate Watergate committee. His oft-repeated question (“What did the president know and when did he know it?”) is suddenly as apt today as it was in 1973.

Even if you put the most charitable Fox News interpretation on everything (the Trump Tower meeting was a dud; the oppo research was worthless; and no one bothered to inform the candidate), Trump Jr’s emails raise another problem for the White House.

The original email to the president’s oldest son from the publicist Rob Goldstone passed along high-level gossip from the Russian oligarch Aras Agalarov that this assistance “is part of Russia and its government’s support for Mr Trump”.

That, in itself, was news that cried out to be passed along to stroke Trump’s ego. Wouldn’t Trump Jr or Kushner have mentioned during some family gathering during the campaign that the former communist Vladimir Putin had become a card-carrying Republican willing to do anything to help his favored candidate humiliate Clinton?

Donald Trump Jr may have thought that he was devilishly clever by voluntarily releasing the email chain just ahead of a New York Times story. But by putting it out himself, he made it impossible for Republicans with any grasp of reality to denounce the bombshell as “fake news”. The best that they can now muster – and it was the underlying theme of Hannity’s fawning interview – is to shout: “fake interpretation.”

Somehow that doesn’t have the same ring.