By JOHN PARKINSON, ABC News

(WASHINGTON) — Jay Clayton, the Trump administration’s controversial pick to become U.S. attorney in the Southern District of New York, is poised to testify on Capitol Hill Thursday afternoon, as his anticipated nomination to the federal district court continues to face stiff criticism from Democrats.

Clayton, the current chairman of the Securities and Exchange Commission, is slated to testify at a hearing entitled Capital Markets and Emergency Lending in the COVID-19 Era, although House Financial Services Committee Democrats are expected to grill him on his expected nomination.

President Donald Trump has not yet formally nominated Clayton to the post, which requires Senate confirmation. Both of New York’s senators, Charles Schumer and Kirsten Gillibrand, have vowed to oppose Clayton, who was confirmed as SEC chairman in a bipartisan 61-37 vote on May 2, 2017.

Attorney General William Barr announced in a news release late last Friday night that Geoffrey Berman, who served as the U.S. Attorney for the Southern District of New York, would resign from the position to create room for Clayton, but Berman soon issued a statement refusing to step down voluntarily, directly contradicting the attorney general.

Barr then released a statement Saturday announcing he asked Trump to fire Berman — effective immediately — in light of his resistance, complaining Berman chose to create a “public spectacle over public service.”

Later Saturday, Berman agreed to vacate his post “effective immediately” after President Trump sought to distance himself from the firing. Berman also noted that Barr decided to “respect the normal operation of law and have Deputy U.S. Attorney Audrey Strauss become Acting U.S. Attorney,” instead of Barr’s hand-picked replacement, Craig Carpenito.

Barr is facing calls for his resignation and threats of impeachment from Democrats. He’s expected to testify at the House Judiciary Committee on July 28.

Under Berman’s leadership, the office prosecuted the president’s former personal attorney Michael Cohen and filed sex trafficking charges against Jeffrey Epstein, a friend of the president who killed himself in federal jail less than two months later.

Trump’s current personal attorney, Rudy Giuliani, continues to be investigated by the Manhattan office — facing scrutiny for his financial ties to Ukraine, according to sources.

White House Press Secretary Kayleigh McEnany denied Berman was fired for investigating Trump’s associates, telling reporters that Clayton “wanted to go back to New York City” and Trump “wanted to nominate him to this position in SDNY to keep him in the government as he returns to New York.”

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