The worst-kept secret in all of American politics is that senior Republicans in Congress and the Trump administration worry not just about the president’s potential wrongdoing, but with his mental fitness to hold high office. Among themselves, and speaking to reporters off the record or on background, Republicans say incredibly alarming things. “One figure close to the White House,” The Washington Post’s White House bureau chief Phillip Rucker reports, “mused privately about whether Trump was ‘in the grip of some kind of paranoid delusion.’”

We can only guess who Rucker’s source is, because this sentiment is widely shared, but we can safely assume it’s someone of real influence, because the quote landed in the third paragraph of a front-page story. What Republicans of real influence say when their names are attached to their quotes thus represents one of the most stunning derelictions of public duty in recent memory. If, as The New Yorker’s legal writer Jeffrey Toobin put it, President Donald Trump’s decision to fire FBI Director James Comey was “a grave abuse of power,” Republican congressional leaders, nearly all rank-and-file members, and senior administration officials are engaging in a similarly grave abdication of it.

When Trump tried to bully Comey into silence via Twitter on Friday, House Speaker Paul Ryan repeated the go-to dodge he’s used for months to enable the indefensible things Trump does. “I’ve decided I’m not going to comment on the tweets of the day or the hour,” he said. “No one is disputing the fact that the president has the right to hire or fire an FBI director.”

Speaker Ryan on today's news: pic.twitter.com/KUBweFj7DH — Jake Tapper (@jaketapper) May 12, 2017

But the truly shocking thing was what Ryan added separately. “I’m focusing on what’s in my control, and that is what is Congress doing to solve people’s problems.” Stipulating that what Ryan means by “solving people’s problems” is removing their health insurance to cut rich people’s taxes by hundreds of billions of dollars, what’s really amazing is how Ryan expresses his conception of what is within the power of the body that he leads. Ryan isn’t just choosing to look the other way; he is actually denuding himself and the Congress of some of its most basic functions.

Here is a partial list of things that are within Ryan’s control, or control of Congress more generally: whether Trump releases his tax returns; whether the House and Senate allocate the resources required to investigate Russian meddling in the election; whether Congress establishes a non-partisan investigative body to probe that issue; whether the attorney general can get away with lying to Congress; whether the attorney general can get away with unethical trespassing into issues he’s supposed to be recused from; whether the deputy attorney general or some other, more independent figure oversees the Justice Department’s Russia probe; whether a president who poses a threat to the security of the country (whether through foreign entanglements or ill temperament) will endanger the public for four years.