Newly independent Rep. Justin Amash Justin AmashInternal Democratic poll shows tight race in contest to replace Amash Centrist Democrats 'strongly considering' discharge petition on GOP PPP bill On The Trail: How Nancy Pelosi could improbably become president MORE said on Sunday that he believes Speaker Nancy Pelosi Nancy PelosiPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' On The Money: Anxious Democrats push for vote on COVID-19 aid | Pelosi, Mnuchin ready to restart talks | Weekly jobless claims increase | Senate treads close to shutdown deadline Trump signs largely symbolic pre-existing conditions order amid lawsuit MORE (D-Calif.) is making a mistake by not calling for impeachment proceedings to begin on President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE.

"From a principled, moral position she is making a mistake. From a strategic position, she’s making a mistake," Amash told CNN's Jake Tapper Jacob (Jake) Paul TapperThe media's misleading use of COVID-19 data Julia Louis-Dreyfus: 'We can't spend much time grieving' Ginsburg Pence aide dismisses concerns rushed vote on Trump nominee will hurt vulnerable senators MORE Sunday on "State of the Union."

Amash, who announced he is leaving the GOP last Thursday, had been the only Republican in Congress to call for impeachment proceedings. ADVERTISEMENT

Despite a growing number of Democrats calling for impeachment after the allegations of obstruction of justice against Trump outlined in former special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's report, Pelosi has maintained she will not begin proceedings at the moment.

"I do believe there's a strong case, I believe she believes there is a strong case...if so move forward," Amash said on Sunday.

The Hill reached out to Pelosi's office for comment.

Amash also said most of the public likely hasn't read the more than 400-page-long Mueller report, and expect their representatives to do so.

He told Tapper, however, he believes probably less than 15 percent of Congress – Republicans and Democrats– have read it.

"I think a large number of them would reach the same conclusion, some would reach different conclusions," Amash said on how Republicans would react after reading the report.

"Look at the evidence presented. I think anyone would be indicted for that conduct, anyone that's not the president of the United States," he said.

Although he was the only Republican to publicly support impeachment, Amash said members of his former party privately expressed agreement.

Amash said Republicans in Congress and "high-level officials," without naming names, thanked him after he said impeachment proceedings should being.

Many did so again after he announced he was leaving the party, he said.