FILE - In this March 26, 2012, file photo, Gregory Katsas, of Washington, a lawyer who argued before the Supreme Court on behalf of the National Federation of Independent Business about the Anti-Injunction Act, speaks outside of the Supreme Court in Washington. President Donald Trump has tapped Katsas, one of his own White House attorneys for a judgeship on one of the most important federal appeals courts, opening the door for confirmation hearing questions about the legal controversies that dominated the first seven months of Trump's presidency. (AP Photo/Jacquelyn Martin, File)

WASHINGTON - President Donald Trump has tapped one of his own White House attorneys for a judgeship on one of the most important federal appeals courts, opening the door for confirmation hearing questions about the legal controversies that dominated the first seven months of Trump's presidency.

Gregory Katsas was nominated Thursday to serve on the U.S. Court of Appeals for the District of Columbia Circuit. Katsas, the deputy White House counsel, was a former Justice Department official under President George W. Bush. A biography on the White House's website says he has argued more than 75 appeals, including the constitutional challenge to President Barack Obama's Affordable Care Act before the Supreme Court.

He would replace the libertarian-leaning Judge Janice Rogers Brown, who retired this summer. The court is influential, in part because of its role in adjudicating many of the orders and laws put forth by the administration. It is sometimes called America's second highest court because it can be a stepping stone to the Supreme Court just a few blocks away.

Katsas, once a law clerk to Justice Thomas, has served in high-ranking Justice Department roles, including as head of the civil division that has responsibility for defending the administration's policies against court challenges. He is part of the steady stream of Jones Day law firm partners who have flowed into the Trump administration, including White House counsel Don McGahn.

So many Jones Day attorneys work in the White House that the counsel's office issued a blanket ethics waiver for them so that they can maintain contact with their former colleagues without running afoul of ethics provisions. The firm's lawyers continue to represent members of the Trump campaign outside the White House.

Senators are likely to grill Katsas about his time at the Trump White House, which has been rocked by legal problems. That includes expanding investigations by Congress and the Justice Department into Trump campaign ties to Russia, which U.S. officials say interfered in the 2016 election.

Trump's initial attempt at an executive order temporarily banning travel to the U.S. from several Muslim-majority countries hit roadblocks in the courts. On his second attempt, the Supreme Court allowed only a sharply scaled back version of the order to go forward pending arguments scheduled for October.

And a federal judge said in July that he's not likely to reinstate an executive order to cut funding from so-called sanctuary cities that limit co-operation with U.S. immigration authorities.

Former colleagues were quick to praise the nomination. John O'Quinn, who worked with Katsas in the Justice Department, called him "an incredibly talented lawyer who has a servant's heart and a humble demeanour."

"I can't think of anyone who would have better judicial temperament," he said.

There were no immediate indications that Katsas would face intense opposition from Democrats on the committee. But even if they have qualms about Katsas' nomination to the lifetime position, they have no way to block Katsas — there is no filibuster left for nominations and no "blue slip process" for the D.C. Circuit, which allows senators in a nominee's home state to submit their written opinions of him.

News from © The Associated Press, 2017