Winston Churchill is supposed to have said: “With integrity, nothing else counts. Without integrity, nothing else counts.”

In fact, that seems to be one of those Churchillian epigrams that Churchill never actually got around to saying. But it captures an important truth about politics, that dishonor is like a cancer that spreads inexorably as it feeds upon ambition, protects itself with lies and doubles down with cover-ups.

Looking at the chaos in the White House these days, I worry about inexperience, incompetence and lack of judgment. But maybe I worry most about an utter lack of integrity — and the way it is proving infectious.

The contagion of dishonor has spread irresistibly through the White House staff, turning aides into con artists. Indifference to ethics has spread through the cabinet and agencies, resulting in endless scandals. And the epidemic has rippled through much of the G.O.P. (with some heroic exceptions), turning lawmakers into enablers and hypocrites.

The Rob Porter affair, for example, isn’t just about Porter any more but about what seems to be a cover-up and a dismissiveness toward domestic violence. John Kelly, the White House chief of staff, claimed that he had removed Porter within 40 minutes of learning of credible allegations of Porter’s domestic abuse; to listen to F.B.I. testimony, it now seems it may have been seven months.

President Trump said on Wednesday that he is against domestic violence. But when you have to say that, something is wrong.

We have a president who has himself been accused of domestic violence (an allegation of rape by his first wife that she later retracted), who has lost two aides to accusations of domestic violence, whose chief of staff (a retired four-star Marine general) in 2016 praised a colonel as a “superb Marine officer” after he had been accused of sexually harassing two women. More broadly, while I understand the sorrow people feel for a colleague who is self-immolating, the White House’s initial comments came across as discounting one of the most common kinds of violence in America today.

Some 28,000 Americans are sent to emergency rooms each year because of domestic violence. Almost 20 people are victimized each minute. This isn’t a fringe issue: It claims far more American lives than terrorism. The White House would never be caught with a bank robbery suspect on its staff, so why tolerate someone alleged to be a wife beater?

The answer has to do, I think, with a lack of integrity, an absence of a moral compass, a narcissism in which the all-consuming need becomes to protect oneself and one’s boss.

Lack of integrity may also be the best way to capture the morphing scandal of the pre-election $130,000 payoff to a porn star to apparently keep quiet about an affair with Trump. It’s bad enough that Trump appears to have been cheating on Melania right after she had their baby (“Oh, don’t worry about her,” he is said to have told the actress). But with the payoff and reported cover-up, Trump is betraying all of us.

When The Wall Street Journal first reported the porn-star payout by Michael Cohen, Trump’s longtime lawyer, Cohen denounced the report as a “false narrative” of “outlandish allegations.”

Oops. Take two. This week, Cohen confirmed the payment in a statement saying that he “facilitated” the transfer with his own cash. It doesn’t seem quite true, as some news organizations reported, that Cohen precisely denied that he had been reimbursed. Cohen’s statement was artful. He denied that he had been reimbursed by either the Trump Organization or the Trump presidential campaign, but not that he had been reimbursed by someone else — say, by Trump himself. (The White House did not respond to my inquiry about whether Trump had personally paid the $130,000.)

Sometimes politicians, liberals and conservatives alike, are unprincipled in pursuit of principles they are passionate about. But Trump aides don’t seem to believe in any cause larger than themselves or their leader.

That’s alarming because of the risks that even worse might lie ahead. When self-absorbed people are caught in a growing scandal, they overreach. In this case, that might mean the firing of Robert Mueller or Rod Rosenstein, or some military clash that changes the subject. To be clear, I don’t think officials would deliberately turn to war as a solution to political problems, but we all have a remarkable ability to persuade ourselves that what is good for us is also good for the country.

Every administration suffers embarrassments. But when there is a basic lack of integrity at the top, these do not easily self-correct; rather, they build upon themselves because of an impulse to cover up and layer new deceptions on top of old deceit. That seems to be what is happening in both the Rob Porter and porn-payoff scandals.

The risk is that this stain continues to spread, metastasizing and bringing down everything around it. And to me, it looks as if the Trump administration is now metastasizing.

<NICHOLAS D. KRISTOF>