After House Intelligence Committee Chairman Adam Schiff announced a new, wide-ranging probe into Russian election meddling and President Trump's foreign business dealings, Judge Andrew Napolitano warned the president that he is about to be in Democrats' "cross hairs."

During his State of the Union address Tuesday, just one day before Schiff (D-Calif.) revealed his investigation, Trump decried what he called "the politics of revenge" and "partisan investigations."

After the announcement, Trump was quick to criticize Schiff 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.

So now Congressman Adam Schiff announces, after having found zero Russian Collusion, that he is going to be looking at every aspect of my life, both financial and personal, even though there is no reason to be doing so. Never happened before! Unlimited Presidential Harassment.... — Donald J. Trump (@realDonaldTrump) February 7, 2019

....The Dems and their committees are going “nuts.” The Republicans never did this to President Obama, there would be no time left to run government. I hear other committee heads will do the same thing. Even stealing people who work at White House! A continuation of Witch Hunt! — Donald J. Trump (@realDonaldTrump) February 7, 2019

On "Fox & Friends" Thursday morning, Napolitano said there needs to be some suspicion or kernel of evidence to launch a criminal investigation, but that it not the case for Congress.

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 Congress can investigate whatever it wants and it can literally engage in a witch hunt, whether there's evidence there or not," Napolitano said. "He's about to be in their cross hairs. I don't know where it's going to go. He has a lot of defenses."

He said the most important of those defenses is executive privilege, but he predicted that Schiff is going to look at "extra-presidential behavior" and "pre-presidential behavior."

As for the difference between the House Intelligence Committee investigation and Mueller's probe, Napolitano explained that Congress can control the former but not the latter.

“This is a shadow investigation. If one of Bob Mueller’s people revealed what went on before the grand jury, that's a criminal event. If one of Adam Schiff’s people revealed what they learned, they can do it with impunity," Napolitano said. "So Congress can conceal or reveal whatever they want."

He noted that Schiff's committee voted on Wednesday to hand over to Mueller interview transcripts generated by the panel's previous Republican-led Russia investigation.

"So Mueller can see if anybody lied," Napolitano said.

Watch the "Fox & Friends" segment above, and sign up for Fox Nation to get more from the judge on "Liberty File."

'A Slow-Motion Coup Attempt': Fitton Blasts Schiff, Dems' New Trump Investigations

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

Judge Nap: Federal Prosecutors 'Not on Witch Hunt' in Probe of Trump Inaugural Committee