Within a few minutes on Tuesday, Donald Trump’s long-time personal lawyer Michael Cohen pleaded guilty to eight federal criminal charges, and his former campaign chairman Paul Manafort was separately found guilty on another eight criminal charges.

What’s more, when Mr. Cohen admitted to campaign-finance crimes for paying or arranging hush money to women who said they had affairs with Mr. Trump, he swore under oath that he was acting at the behest of his boss, suggesting Mr. Trump broke laws himself.

It was, by any historical standard, a momentously dark moment for the United States presidency. So why is there a nagging sense of doubt about how much it matters?

Story continues below advertisement

It is not so much that the testimony of someone such as Mr. Cohen, an untrustworthy source of information, must be taken with a grain of salt. (An audio recording somewhat backs his claim.) Nor that crimes of Mr. Manafort, who raked in millions as a political adviser to foreign autocrats, were unrelated to his work for Mr. Trump. Close association with such a man would be devastating to most presidents.

More so it is that Mr. Trump has already so demeaned his office that he and what surrounds him have all but lost their capacity to shock.

This is a President who boasted on tape about sexually assaulting women; who advanced a policy of separating children and infants from their parents at his country’s border; who on whims launches trade wars against some of America’s closest allies; who continually engages in race-baiting if not outright racism, including overt Islamophobia and an obsession with football players who peacefully protest police violence; and on and on.

Yet amid the cacophony, nobody can afford to grow numb, even if that numbness is among the most damning indictments of Mr. Trump’s presidency.

What could have sunk other presidents – close association with criminals, if not illegal conduct themselves – may not be enough to sink him. But it cannot be accepted, by Americans and by those around the globe who have long looked to their country as a shining example of how a democracy should be run, as the new normal.