Historians of the modern presidency keep a special shelf for Richard Nixon — a noted place for a corrupt, power-mad and paranoid man who trampled constitutional ideals in his quest to hang onto his office. But Nixon must relinquish his title as modern history’s most corrupt president to a man who would leave him in the dust: President Donald J. Trump. Even Nixon would likely be alarmed by his behavior.

For all his conniving, all of his cover-ups, all of his lies, Nixon had an appropriate appreciation for foreign rivals, an understanding of the existential threats represented by our adversaries. Not so Trump. He would gladly hand over the keys to the kingdom to Russia — or North Korea, for that matter — as long as their strongmen showed him the deference which he craves.

In an alarming display of ignorance and arrogance, Trump told ABC’s George Stephanopoulos last week that he would accept any incriminating information about his political opponents that Russia or any other foreign country might provide. Casually referring to such intrusions as “opposition research,” Trump said: “I think you might want to listen. There’s nothing wrong with listening … It’s not interference.”

The president said that while repeating, with a straight face, his frequent refrain that special counsel Robert Mueller’s investigation, which centered on Russian interference in the 2016 presidential election, was a “witch hunt.” (Trump has also told Stephanopoulos that he likes “the truth … I’m a very honest person” — a claim that is a funhouse mirror reflection of reality.)

Trump’s campaign marks the first time in American history that a foreign power is known to have intervened in a U.S. election, a stunning disruption of our revered political processes, a cunning use of soft power that would have left our intelligence services envious had it not happened to us. All of the years of the Central Intelligence Agency’s interference in lands from the Middle East to South America never yielded a result quite so neat and clean. We were successfully attacked by a foreign power without a shot fired or a body dropped. Russia’s assistance may well have been the boost that put Trump over the finish line.

And unlike Nixon, who at least had the good sense to be ashamed of his dirty tricks, Trump has just told a national audience that he would welcome Russian assistance should they offer it again. Reminded that his own FBI director, Christopher Wray, has said that any such intrusion should merit an immediate report to federal authorities, Trump angrily retorted, “The FBI director is wrong.” The president said he might not report any such contact by a foreign power.

Trump’s perfidies are so astonishing — so bold and bald-faced — that many Americans are left speechless, jaws dropped to the floor, unable to fully grasp the ramifications. Others, however, embrace Trump’s lawlessness, excuse his treachery, aid and abet his abuses. Here’s another distinction from the Nixon era: The U.S. attorney general, William Barr, has attacked those who point out Trump’s malfeasance. Barr, indeed, has launched a broadside against U.S. intelligence agencies for daring to investigate Russian interference in the 2016 election.

And there are still other differences more troubling, more profound. Nixon ultimately resigned rather than face impeachment; he was rapidly losing the support of leading Republican office-holders as well as the allegiance of regular GOP voters. His presidency was unsustainable.

Trump lacks the self-awareness or sense of shame to resign. Besides, he continues to enjoy the support of the vast majority of Republican politicians from the U.S. Senate down to small-town courthouses. GOP voters, too, have shown a loyalty that would have thrilled Jim Jones. As Trump infamously put it during his campaign, “I could stand in the middle of Fifth Avenue and shoot somebody, and I wouldn’t lose any voters.”

That suggests a rot that goes much deeper than one foolish narcissist and his chosen claque. A substantial minority of American voters are ready to throw out the U.S. Constitution, blow up cherished democratic traditions, and embrace a foreign dictator — so long as they can keep the man whose presidency is built on white nationalism. This is a putrefaction at the heart of the American system, a malignancy at the core.

The time for impeachment may have arrived, but it won’t cure what ails us.