Judge Andrew Napolitano said the report of classified information being openly revealed by President Trump to the Russians is the "most potentially catastrophic" yet.
Napolitano said that there were a "finite number" of people in the room when Trump met with Russian envoys last week.
He said that one of those people is either directly or indirectly the person that anonymously leaked their recollections to the Washington Post on Monday.
National Security Adviser Gen. H.R. McMaster said in a brief press appearance that the Post's story is false.
"I was in the room. It didn't happen," he said.
Napolitano said that the intelligence community is required by law to disclose such reported leaks to Congress, which has not happened.
Chris Stirewalt said that, true or false, the story was like a big "red steak" thrown to congressional Democrats looking to extend their Trump-Russia narratives.