Throughout his career, Donald Trump gathered around himself an extraordinary number of grifters and crooks, who plainly saw in him both a kindred spirit and a vehicle for their own corrupt ambitions. Some of them are in jail right now.

But there’s another kind of corruption Trump has brought to Washington, one that extends even to those who are not simply trying to use their association with government to get rich. It’s a moral and institutional corruption, stretching its tentacles through every agency Trump can enlist to protect himself from accountability and public scrutiny.

In many agencies, Trump has sought to drive nonpartisan public servants out of government so that only cronies and hacks will remain. In other cases, the political leadership of the agency makes clear to everyone in it that whatever they used to think their mission was, now they have one priority above all others: Protect Trump.

No one has embraced that purpose with more enthusiasm than Attorney General William P. Barr, who is working to make the Justice Department an extension of Trump’s personal legal team:

The Justice Department urged a federal appeals court on Tuesday to overturn a ruling requiring President Donald Trump’s accounting firm to turn over years’ worth of the president’s financial records to Congress, suggesting Democrats are attempting to “harass” Trump rather than legislate.

In a 30-page filing submitted to the U.S. Court of Appeals for the District of Columbia Circuit, Justice Department lawyers argued that efforts by congressional Democrats to access Trump’s financial information — from accounting firm Mazars USA — were impermissible because they lacked a clear “legislative purpose.” It’s the first time the Trump administration has waded into the delicate dispute. Trump’s personal attorneys previously made similar arguments.

This filing is not just an embarrassment in its preposterous legal reasoning and fantastical positions on the separation of powers. It’s also an affront to the idea of the Justice Department as an institution that exists not to serve the president but to serve the law. And it shows just how deeply Trump’s corrupting influence has reached.

Experts on separation-of-powers issues will tell you that legally speaking, Trump doesn’t have a leg to stand on. “What the courts have made clear repeatedly is that congressional oversight power is incredibly broad,” Brianne Gorod of the Constitutional Accountability Center told me in April. Lawmakers in Congress have subpoena power, and they can use it to conduct pretty much whatever kind of oversight they want. They don’t have to satisfy the executive branch that they have good enough reasons for doing so, or that their motivations are pure and apolitical.

But now the Justice Department is asserting that they do. And this is coming, we should note, from the party that mounted eight separate congressional investigations of Benghazi, which Rep. Kevin McCarthy, now the leader of House Republicans, admitted were meant to damage Hillary Clinton.

Nobody even bothered to pretend that there was a sincere “legislative purpose” to the fifth and sixth and seventh and eighth Benghazi investigation (you might have noticed that consular security, like proper email management practices, is not actually something Republicans care deeply about as a matter of principle). But they had the power to stage them, so they did. If every bit of oversight that had a political motivation were shut down by the courts, there would be no oversight at all.

And it’s particularly ludicrous to suggest that investigating Trump’s finances is illegitimate. In fact, it’s Trump’s corruption that makes the “legislative purpose” of investigating him so clear and urgent. Trump has shown over and over again how our current laws are inadequate to maintain something resembling integrity in government, since we rely so heavily on norms of behavior that until now everyone respected. Jimmy Carter put his peanut farm in a trust; Barack Obama wouldn’t even refinance his mortgage while president to avoid any appearance of impropriety.

That was just how things were done. Until Trump. Only if we know the full extent of his conflicts of interest and the ways he is profiting off the presidency can we determine if we need new laws to restrain corruption in the Oval Office.

That’s not the only front where the battle to keep Trump’s finances secret is playing out. The president and the Republican Party just filed suit against the state of California to stop a recently passed law that requires presidential and gubernatorial candidates to release five years of tax returns in order to appear on the ballot in that state. While there are legitimate questions about the constitutionality of the law, I was struck by a tweet from Republican National Committee chair Ronna McDaniel — who, it must be noted, is such a spectacular lickspittle that she literally changed her name after Trump found it displeasing. “It certainly doesn’t bode well for Democrats heading into 2020,” McDaniel said, “that their best bet for beating @realDonaldTrump is to deny millions of Californians the ability to vote for him.”

California is, of course, not trying to deny anyone the ability to vote for Trump. It’s trying to force him to release his tax returns, on the assumption that faced with the prospect of not appearing on the ballot he would cough them up. But McDaniel assumes just the opposite: that making his returns public and disclosing where he actually gets his money would be so politically catastrophic that it would be worth not appearing on the California ballot in order to avoid doing so.

That reveals the essence of what Trump has demanded from all Republicans and now from all parts of the federal government. Not only must they protect him, but they must do so knowing that they do it for the worst possible reasons. Everyone acknowledges that his corruption is so deep and encompassing that were he subjected to the same kind of scrutiny every president faces, it would be a disaster. So every institution of government must be conscripted to avoid that possibility.