In his first two years in office, President Trump battled the Democrats' charge of "Russia collusion," which he dismissed as a hoax.

Turns out he was right, as special counsel Robert Mueller concluded after spending as much as $42 million in taxpayer funds.

The most recent charge that his phone call with Ukraine's president was impeachable was rejected last week by the Senate.

But there will be more coming.

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That's according to Rep. Devin Nunes, R-Calif., a lead investigator of the origins of the Obama administration's probe of the Trump campaign.

In an interview Monday on "Fox & Friends," he said Democrats who have absolutely no tolerance for Trump could come up with another hoax.

"I'd say that old habits die hard," Nunes said. "They've done nothing else for their entire time that they've controlled Congress and don't forget the Democrats on the intelligence committee started this right after Trump was elected so that’s going over three years."

He suggested the Democrats' next move may be to target former National Security Adviser John Bolton.

"They may concoct a new hoax, I'm not sure that the American people will believe it, but you can be sure of one thing, the mainstream media will support whatever it is the narrative is that they want to build," he continued.

House Speaker Nancy Pelosi already has promised to continue investigating him.

"We will continue to do our oversight," she said, and decisions would be made as "opportunities" rise.

Nunes said he wasn't sure Democrats knew "how to do anything else."