House Financial Services Chair Maxine Waters (D-Calif.) tweeted on Tuesday that President Trump should be "imprisoned and placed in solitary confinement," and called for Republicans to "stop Trump's filthy talk of whistleblowers being spies" and his "mob language."

Catch up quick: Waters' tweet came after the president suggested the whistleblower, whose complaint is at the heart of a controversy involving himself and Ukraine, is "almost a spy." Trump said that the U.S. used to respond to "spies and treason ... a little differently than we do now." Waters also noted on Tuesday that "for now, impeachment is the imperative."

The big picture: Plenty of Democrats were disturbed upon reviewing the whistleblower complaint. House Intelligence Chairman Adam Schiff (D-Calif.) compared the president to a "Mafia boss" engaging in a "classic organized crime shakedown" after the transcript of Trump's call with the Ukrainian president came out.

Go deeper: Intelligence community watchdog refutes Trump's whistleblower claims