It was long clear that Donald Trump would be an incompetent president. But over the past week he has proven himself to be a dangerously incompetent president.

In the opening weeks of his presidency, Trump's unforced errors were embarrassing — but, one could argue, at least the botched rollout of his immigration executive order rendered it vulnerable to legal attack, his poor negotiating skills complicated the passage of his slipshod health-care bill and his inattention to detail enabled his surprisingly capable foreign policy staff to limit the damage he could do. And, some Democrats noted, the president's flailing has already helped create the conditions for an anti-GOP wave in 2018.

Then Trump fired James Comey and had his staff mislead the public about how and why, before admitting that the FBI's ongoing investigation of his campaign's possible ties to Russia was a major reason he removed the now-former FBI director. Legal minds are debating whether this was obstruction of justice. But consider how remarkable it is that Trump may not have contemplated this reaction, and to the point that he freely admitted his possible culpability on national television. The president reportedly thought no one would mind if he fired the man presiding over a national security investigation involving his own campaign. In the process, he imperiled the independence of an organization entrusted with extraordinary powers.

Now The Washington Post reports that the day after he fired Comey, Trump revealed highly classified information to the Russian foreign minister and ambassador. U.S. officials apparently obtained the material, which concerned Islamic State plotting, from a foreign ally and did not have permission to share the information with Russia. Though few specific details could be reported, there are a variety of dangerous potential consequences. Not only could the information's disclosure imperil an intelligence relationship with a helpful government, but it could also reveal a secret intelligence asset to a foreign adversary working at cross purposes to the U.S. and its allies.

Compounding the insult, the accounts in The Post suggest Trump may have revealed the information in order to boast to his foreign visitors about the quality of the intelligence briefings he receives, as if they would not have known that the president of the United States has access to impressive amounts of secret material. The picture is not so much of conspiracy or malevolence, but of unfathomable carelessness.

Given his many business failures, the only realms in which Trump has proven himself adept are those of popular manipulation and treachery, along with the related arts of show business. No doubt he will use them in the coming days to mislead and scapegoat his way out of accountability.

If, for the first time, one could sketch out a somewhat plausible case for impeachment following the president's admission that he fired Comey over Russia, one could now piece together an argument for removal due to presidential incapacity based on the revelation that Trump betrayed dear national security secrets in order to impress the Russian foreign minister. The president may have just shown that he can and will harm the nation's security without any apparent intent to do so.

Impeachment probably is not realistic, but Congress must engage in more aggressive investigation and checking and balancing. Republicans who savagely attacked Hillary Clinton over the petty email server scandal will now show where their true concerns lie — with party or with country. No agenda is worth pretending this presidency is good for the nation.