Charles Krauthammer reacted to news that Special Counsel Robert Mueller expanded his investigation to include possible obstruction of justice by President Trump.
Mueller was originally named to investigate claims of collusion between Trump and the Russians.
However, in the wake of ex-FBI Director James Comey's firing, questions were raised about Trump's conduct in meetings with him.
Krauthammer called it a "classic case of a special counsel expanding the scope of his investigation."
'Thin Blue Line Held Today': GOP Rep Recounts Police, Reps' Heroism After Scalise Shooting
'Back in Iraq' Without His Weapon: GOP Rep. Describes Attack
Rep. King on Scalise Shooting: There Are 'Psychotic People' on Both Sides
"The metastasis has begun," he said.
Krauthammer said Mueller is now the "most powerful man in Washington."
He pointed out that although Trump can legally have Mueller fired, it would likely be politically devastating to him.
Watch the clip above.
WATCH: Man Walking Dog Captures Moment Scalise Shooter Opens Fire
'Dad's OK': IL Lawmaker Describes Phone Call to Family After Scalise Shooting
Gov. McAuliffe on Scalise Shooting: 'There Are Too Many Guns on the Street'
