In shocking news on Tuesday, U.S. ambassador to the European Union Gordon D. Sondland changed his congressional testimony to confirm what everybody who isn't a fool already knows to be true — namely, that the president demanded a political quid pro quo from Ukrainian president Volodymyr Zelensky.

That way of putting it does a decent job of capturing the surreal situation in which all of us find ourselves. Trump has insisted from the beginning that he did nothing wrong in his late July call to Zelensky — indeed that the call was "beautiful" and "perfect" — and he has taken this stance despite the fact that his own White House released an edited readout of the call that appears to show Trump doing precisely what he's been accused of doing by congressional Democrats and a series of witnesses in sworn testimony. It's as if Richard Nixon had responded to the first reports of the Watergate break-in by denying he was behind it while simultaneously releasing evidence showing that he was, and then began describing the effort to steal campaign secrets from his opponents as perfectly fine and even admirable.

Just six weeks into an impeachment investigation, the White House's defense has already crumbled — but it's hard to see how anyone could have thought it would do otherwise.

In a rational world, the brazenness of Trump's actions — using the threat of withholding aid to a foreign country to get its government to announce the opening of a (baseless) criminal investigation against the American president's political rival — would provoke thoroughgoing disgust in public spirited and patriotic Americans of every political stripe. In a rational world, the haplessness of Trump's self-defense would make him a national laughingstock.

But this is not a rational world. Instead, it's a world in which conservative so-called journalists spend their days pretending the identity and supposed nefarious agenda of the whistleblower who first alerted congressional Democrats to possible presidential malfeasance is somehow significant — as if his or her claims haven't been verified by numerous other witnesses.

It's a world in which the ranking Republican member of the House intelligence committee used his entire time questioning Sondland to discuss the Steele dossier — which played the identical red-herring role during the Mueller investigation into Russian meddling in the 2016 election.

It's a world in which a Republican senator announces that he will deliberately avoid reading transcripts of testimony from witnesses in the matter — because he's decided, for no clear reason at all, that they are unreliable.

And it's a world in which Trump is guaranteed to continue demanding that loyalists defend him unconditionally, no matter how many admirable, trustworthy people testify that he abused the power of his office in acting like a penny-ante mob boss out to shake down a needy member of the neighborhood for protection money.

Not that all Republicans will court humiliation by saying things as flatly untrue and even absurd as the president himself. They will rather fall back on the line currently being pushed by a number of senators: What Trump did was definitely bad, but it isn't so bad that he deserves to be removed from office.

There's just one problem with this approach: We may not yet know everything Trump did, or just how bad it was. On Tuesday, we received transcripts from Sondland and former Ukraine envoy Kurt Volker. Both were bad news for Trump. But what about the witnesses to come? Vice President Mike Pence's aide Jennifer Williams is scheduled to testify on Thursday. Meanwhile, the House Intelligence, Foreign Affairs, and Oversight committees sent a letter on Tuesday to Mick Mulvaney, Trump's acting chief of staff, requesting that he testify on Friday. Mulvaney has already proven himself somewhat … unhelpful in his efforts to defend the president. What might he say under oath?

And that's just this week.

Republicans are likely to find themselves in the position of having to make "yes it's bad, but" arguments as the "bad" gets worse and worse.

We've seen this happen before, with the Mueller investigation. First the line was that the Trump campaign didn't seek electoral help from Russia. Then, when it became clear that it did precisely this, the defense shifted to "so what if Trump wanted help from Russia? What's wrong with seeking to gain every advantage against the evil Democrat Party?" Now we're in the process of re-enacting that shift on the Ukraine call, with Republicans moving from, "there was no quid pro quo" to "maybe there was a little quid pro quo, but that's not so awful." Before you know it, we'll start to hear the case for considering quid pro quo perfectly normal — perhaps even beautiful and perfect.

The late Sen. Daniel Patrick Moynihan (D-N.Y.) used to call this kind of shift "defining deviancy down," and Republicans once venerated him for it. That was back when the GOP and its voters actually thought that upholding the rule of law and high standards of public propriety for political officeholders was important. Not so much anymore. Now all that matters is winning — and that, for Republicans, means that Trump needs to come out of this impeachment intact, no matter what. The result will be an ever-sinking floor.

It sank a little bit lower on Tuesday.