It's perhaps Washington's biggest guessing game since Watergate and the source known as "Deep Throat."
Who wrote the New York Times op-ed piece criticizing the President?
The Poynter Institute's Al Tompkins says the Times is wading into uncharted waters with the op-ed.
"It’s not unheard of, but it’s rare,” he tells WTMJ. “And there ought to be an overwhelming reason to do it.”
President Trump has called the writer, whomever it is, "gutless.”
For the full interview with Tompkins on Wisconsin's Morning News, click in the player below.