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.