WASHINGTON — Solicitor General Noel J. Francisco, the Justice Department official responsible for defending the Trump administration before the Supreme Court, has told the department that he plans to leave, a person familiar with his decision said late Wednesday.
Mr. Francisco’s top deputy, Jeff Wall, will most likely step in as acting solicitor general as the White House searches for a replacement.
While it is not unusual for solicitors general to leave as the Supreme Court winds down its term, Mr. Francisco would be the second high-ranking official to depart in the coming months.
On Monday, Brian A. Benczkowski, the head of the department’s criminal division, announced that he would leave in July. While at the department, he has worked to stem the nation’s opioid crisis and handled the politically charged referral of a whistle-blower complaint about President Trump’s dealings with Ukraine.
The person who spoke of Mr. Francisco’s planned departure did so on the condition of anonymity because he was not authorized to speak to the news media. The Justice Department did not respond to a request for comment early Thursday. CNN first reported Mr. Francisco’s decision to leave.
Since Mr. Francisco, 50, was confirmed as solicitor general in September 2017, he has gone before the Supreme Court to argue some of the most controversial positions taken by the Trump administration, most notably Mr. Trump’s decision in his first week in office to ban people from several predominantly Muslim countries from entering the United States.
The travel ban set off a firestorm in the Justice Department when Sally Q. Yates, then the acting attorney general, refused to comply and was fired. The Supreme Court ruled in 2018 that Mr. Trump had the authority to impose the ban.
The solicitor general got his start in high-level Republican politics when he joined the legal team of George W. Bush, then a presidential candidate, during the 2000 Florida election recount. Mr. Francisco served in Mr. Bush’s administration until leaving in 2005 for Jones Day, the white-shoe law firm that has produced several Trump administration legal hires, including Donald F. McGahn II, the former White House counsel.
Much of Mr. Francisco’s tenure at the Justice Department was overshadowed by the investigation of the special counsel Robert S. Mueller III, who was looking into Russian interference in the 2016 election, any ties between Russia and the Trump campaign, and whether Mr. Trump tried to obstruct the inquiry.
The investigation, which lasted nearly two years, so enraged the president over that time that department officials worried he would fire the special counsel or the top officials overseeing it.
The attorney general at the start of the Mueller inquiry, Jeff Sessions, had recused himself from Russia matters, and the associate attorney general, Rachel L. Brand, resigned in early 2018. That placed Mr. Francisco squarely in the line of succession to oversee the Russia investigation should Mr. Trump fire Rod J. Rosenstein, the deputy attorney general, who had appointed and oversaw Mr. Mueller.
This May, the Supreme Court temporarily blocked Congress from seeing redacted portions of the special counsel’s report that contained grand jury information. Democrats had argued that they needed the materials as part of their impeachment proceedings against the president. Mr. Francisco had argued that the materials should not be released because Congress did not have the right to obtain grand jury materials as part of an impeachment proceeding.
Most recently, Mr. Francisco wrote a brief asking an appeals panel to force Judge Emmet G. Sullivan of the United States District Court for the District of Columbia to grant the Justice Department’s motion to withdraw its case against Michael T. Flynn, Mr. Trump’s first national security adviser.
Mr. Francisco essentially argued that the courts did not have the authority to reject prosecutorial decisions made by the executive branch.
After the Justice Department said it wished to withdraw its case against Mr. Flynn, who had twice pleaded guilty to lying to the F.B.I., Mr. Sullivan tapped John Gleeson, a former mob prosecutor and federal judge, to argue against the government’s position.
Mr. Gleeson said on Wednesday that the government’s motion should not be granted and that the decision to withdraw the Flynn case was a “gross abuse of prosecutorial power” and a political act meant to help an ally of the president’s.
But if the appeals panel agrees with Mr. Francisco and forces Judge Sullivan to grant the motion to withdraw, Mr. Gleeson’s argument could be moot.