Just one day after President Trump decried what he called "the politics of revenge" and "partisan investigations" in his State of the Union address, House Intelligence Committee Chairman Adam Schiff announced a new, wide-ranging probe into Russian election meddling and Trump's foreign business dealings.

Trump was quick to criticize Schiff (D-Calif.) and the investigation, which he called "presidential harassment" and a continuation of Special Counsel Robert Mueller's "witch hunt." He also warned that other Democratic committee chairs could launch their own investigations of his administration.

On "Fox & Friends First" Thursday morning, Judicial Watch President Tom Fitton agreed with Trump that the House Intelligence Committee's new probe is a continuation of the "abusive investigations" already underway.

Watters: Trump May Frustrate Far Left By 'Turning Socialism Into a Political Slur'

'She Should Be Lambasted Politically': Judge Nap on Sen. Warren's Heritage Claim

"The Democratic National Committee [and] the Hillary Clinton campaign manufactured this Russia collusion unicorn theory, and Mr. Schiff is taking it up, and he's going to keep on his party's abuse of power to target President Trump," Fitton argued.

He said Schiff doesn't have the ability to issue FISA warrants against the president, but he can attempt to subpoena him and his administration, and also "fish around" in Trump's personal finances.

He said Schiff essentially becomes "political opposition lead researcher" for whichever Democratic candidate emerges from the primary to take on Trump in the general election.

Fitton said Trump's phrase "partisan investigations" was actually a charitable description of what he's facing from Democrats.

"It's a slow-motion coup attempt. They want to overthrow him. And Democrats have this fever dream of impeachment, and Schiff is setting the groundwork for it."

Watch the "Fox & Friends First" interview above.

Pavlich: Dems Said 'You Have to Believe' Kavanaugh Accuser, Largely Silent on VA Lt. Gov.

'A Come to Jesus Moment': 'Outnumbered' on VA Dem Party's Scandals

Tomi Lahren: Abrams Stuck to Talking Points, Dems' Policy Specifics Are a 'Turnoff' to Voters

Mike Rowe on Trump's SOTU, Dems' Refusal to Stand: 'Dangerous' to Frame Everything as 'This or That'