For nearly a year now, congressional Republicans have been helping Donald Trump cover up something shady in his personal finances and doing so without having any real idea what it is that’s being covered up. The specter of “collusion” — whatever that means exactly — has hung over the Trump/Russia inquiry from day one.

But accounts of Trump’s thinking about the investigation never reveal any trepidation that he’s going to be caught on tape talking to KGB operatives. And congressional Republicans seem reasonably confident that whatever went down during the campaign, Jim Mattis and H.R. McMaster have Trump implementing a “normal” Republican hawkish foreign policy rather than a bizarre Trumpy one advocating for swapping Estonia for the right to develop a golf course in Crimea or whatever.

What Trump worries about, according to many different accounts of his thinking, is what he always worries about — money and the prospect that the impunity for misconduct that he, like many other rich businessmen, has enjoyed throughout his career may not withstand the exacting scrutiny of a special counsel investigation.

A Monday evening Associated Press account of Trump’s reaction to the day’s news said he “has become increasingly concerned that the Mueller probe could be moving beyond Russia to an investigation into his personal dealings,” citing “two people familiar with the president’s thinking.” A Washington Post article with three bylines says that “Trump is also increasingly agitated by the expansion of Mueller’s probe into financial issues beyond the 2016 campaign.” These remarks hark back to a July 19 interview with the New York Times in which Trump called any probing of his business affairs a “red line” that special counsel Robert Mueller shouldn’t cross. And that in turn reminds us of the larger White House effort to build a propaganda case in favor of firing Mueller.

Of course, in a sane world, we really shouldn’t need a special counsel investigation prompted by the firing of an FBI director who was investigating Russian election meddling to get a serious look at the president’s finances. A halfway decent president would voluntarily make meaningful disclosures. And a Congress with even a basic sense of self-preservation would force a president who refuses to make them to do so.

Unfortunately, at the moment, America has neither. We have Trump. We have Mueller. And we have a cover-up in which Paul Ryan, Mitch McConnell, and basically every single House and Senate Republican is complicit, even though they have no way to know what they are covering up.

Trump’s financial opacity is a scandal

George W. Bush put his personal wealth in a blind trust. Jimmy Carter sold his peanut farm. Barack Obama held all his assets in simple diversified index funds. There is a way in which a modern president with a modicum of integrity conducts himself, and Trump has refused to do it.

Rather than liquidate his assets and put the proceeds in a trust, Trump has simply turned over day-to-day management of the family business to his two older sons — sons who continue to serve as surrogates and part of his political operation, even while his oldest daughter and her husband serve as top White House aides. Ivanka Trump is reeling in Chinese trademarks while Eric and Donald Jr. do real estate deals in India. Trump is billing the Secret Service six figures for the privilege of renting golf carts at his golf courses. People with interests before the government can — and do — pay direct cash bribes to the president by joining his Mar-a-Lago club or holding events at his hotel in Washington, DC.

And that’s just what we know about.

The setup is a scandal without rival in the annals of American political venality, and that’s just based on what we know despite the president’s best efforts to keep us in the dark.

Trump’s missing tax returns are very suspicious

Donald Trump likes to claim in public that his tax policies are not going to enrich him personally. For a normal president, a claim like that would be relatively easy to assess based on looking at his tax situation in prior years. For Trump, it’s impossible since he’s declined to release his tax returns to the public. Or, rather, it’s perfectly obvious that Trump is lying — but that’s an inference you have to make based on general principles (Trump lies constantly) rather than on specific knowledge of his tax situation.

When asked about this by Gayle King on the October 20 edition CBS This Morning, Speaker Ryan treated it all as a big joke.

“I don’t know the answer to your question, Gayle! Heh!” Ryan laughed, tossing his hands in the air in mock frustration. “I don’t know exactly how his businesses are structured!”

Unlike Ryan, I am genuinely frustrated that I can’t see what’s in Trump’s tax returns. And the reason I can’t see it that even though House Democrats keep introducing measures that would force Trump to disclose, Ryan keeps blocking the votes. He’s done it again, and again, and again.

Faced with a president whose business interests pose unprecedented opportunities for corruption and conflicts of interest, Ryan has chosen to actively abet an unprecedented level of financial opacity. And in doing so, he’s received the support of basically all of his Republican colleagues in the House and the Senate. It’s appalling.

Trump is right to be worried

There’s an interesting lesson in the fact that Paul Manafort is being brought down by criminal money laundering and tax evasion charges that are at best tangentially related to his work for Trump’s campaign — there’s a lot of white-collar crime happening in America that people are getting away with.

Making white-collar criminal cases is labor-intensive, it’s difficult, and under ordinary circumstances it doesn’t necessarily win a federal prosecutor any friends. The increased post-9/11 emphasis on terrorism cases; the Supreme Court’s unwise decision to acquit Arthur Andersen and reduce Jeff Skilling’s sentence, both for charges related to the Enron matter; and the political pressure to dedicate a wildly disproportionate share of federal law enforcement resources to immigration enforcement have all conspired to transform white-collar criminal prosecution into something of a lost art. Jesse Eisinger’s recent book, The Chickenshit Club, tells the story well if you’re interested.

The point, however, is that Manafort’s criminal misconduct only came to light because he happened to have stumbled into massive political scandal that put his conduct under the microscope in a way that most rich criminals avoid.

By the same token, over the years Trump has been repeatedly fined for breaking federal money laundering rules, been paid millions in hush money to settle civil fraud claims, been caught breaking New Jersey casino law, been caught violating the Hart-Scott-Rodino Act, been caught violating federal securities law, been caught violating New York nonprofit law, and — of course — been accused of multiple counts of sexual assault.

Yet throughout this storied history of lawbreaking, Trump has never faced a major criminal charge. He gets caught, he pays a civil penalty, and he keeps on being a rich guy who enjoys rich-guy impunity — just like Manafort. In an ideal world, the United States would not be systematically soft on white-collar crime. In a second-best world, Congress would discharge its constitutional obligation to engage in meaningful oversight of the executive branch. In the real world, we have Bob Mueller.

The Mueller probe is the closest thing we have to oversight

It would honestly be a shame if the ultimate resolution of the Trump presidency were for the president to be brought down for financial crimes only tangentially related to Russia. A skilled prosecutor with a compelling investigative target brings down his man with whatever charges are available. And Trump’s behavior in firing FBI Director James Comey, lying about why he did it, and then admitting that the real reason was an effort to stymie the Russia investigation is certainly reason enough to regard him as a compelling target.

But the United States is an old republic with a distinguished tradition of constitutional government that affords Congress powers that are both fully adequate to addressing the situation and considerably more appropriate than an FBI investigation.

The Russia matter proper really does require counterintelligence investigators and prosecutorial expertise. But on the critical matter of Trump’s opacity and flagrant corruption, it’s really Congress that ought to be acting.

Yet congressional Republicans, for reasons that seem so obvious today that they don’t even bother to articulate them but that future generations will find baffling, simply refuse to do so. That leaves the country with Bob Mueller standing as the closest thing we have to appropriate oversight of the executive branch. That scares Trump, and rightly so, but it should really scare us all.