During a May 10 meeting with Russia's Foreign Minister Sergei Lavrov and Ambassador to the U.S. Sergey Kislyak, Trump began describing details about an Islamic State terror threat, according to current and former U.S. officials. (The Washington Post)

The Post reports on a stunning development:

President Trump revealed highly classified information to the Russian foreign minister and ambassador in a White House meeting last week, according to current and former U.S. officials, who said that Trump’s disclosures jeopardized a critical source of intelligence on the Islamic State.

The information Trump relayed had been provided by a U.S. partner through an intelligence-sharing arrangement considered so sensitive that details have been withheld from allies and tightly restricted even within the U.S. government, officials said.

The partner had not given the United States permission to share the material with Russia, and officials said that Trump’s decision to do so risks cooperation from an ally that has access to the inner workings of the Islamic State. After Trump’s meeting, senior White House officials took steps to contain the damage, placing calls to the CIA and National Security Agency.

Trump critic and former State Department official Eliot A. Cohen tells me, “For anyone else, if accidental it would be a firing offense. If deliberate, it would be treason.”

It is not clear whether this was accidental or a deliberate attempt to aid Russia. However, in one fell swoop he has told allies he is untrustworthy, thereby impairing intelligence-sharing that is critical to our national security. He has also dumped a bucket of fuel on the fire with regard to the Russia investigation, suggesting he has some affinity or at the very least blind spot with regard to Russia.

Republicans such as Sens. Tom Cotton (R-Ark.) and Ted Cruz (R-Tex.) who continue to play defense for the president will now be put to the test. More responsible members including GOP House and Senate committee members will need to decide if they need to accelerate their investigation into Russia meddling. And certainly, this breaking news adds a further level of intrigue to the unfolding story behind the firing of former FBI director James B. Comey.

Moreover, it is interesting that someone within the administration felt compelled to leak the information, an act sure to infuriate the president. Plainly there are those in the administration who think Trump imperils our security. We should thank these patriots, but also move to investigate and, if need be, remove the man who proves over and over again to be compromised or unfit or both.

Update: Thomas Wright of the Brookings Institution tells me: “This is quite literally the sum of all fears. For the past few months, we have heard that Trump is normalizing. It is nonsense. There are some sensible people around him working around the clock to avert catastrophe but ultimately he is in charge and he will do what he wants, no matter how mad.” He adds, “We are blind and dancing on the precipice.”