WASHINGTON (AP) -- The Trump administration on Thursday asked the Supreme Court to let the president fire a member of the Federal Trade Commission, the latest in a string of emergency appeals over the president's removal power.

President Donald Trump moved to fire Rebecca Slaughter in the spring, but lower courts ordered her reinstated because the law only allows commissioners to be removed for problems like misconduct or neglect of duty.

The Justice Department, though, argues that the FTC and other executive branch agencies are under Trump's control and the president is free to remove commissioners without cause.

The justices already have allowed the firings of several other board members of independent agencies. It has suggested that his power to fire has limitations at the Federal Reserve, a prospect that could soon be tested with the case of governor Lisa Cook.

The fight over the president's power to fire could prompt the court to consider overturning a 90-year-old Supreme Court decision known as Humphrey's Executor. In that case from 1935, the court unanimously held that presidents cannot fire independent board members without cause.

The decision ushered in an era of powerful independent federal agencies charged with regulating labor relations, employment discrimination, the airwaves and much else. But it has long rankled conservative legal theorists who argue the modern administrative state gets the Constitution all wrong because such agencies should answer to the president.

The agency at the center of the case was also the FTC, a point cited by lower-court judges in the lawsuit filed by Slaughter. She has ping-ponged in and out of the job as the case worked its way through the courts.

The FTC is a regulator created by Congress that enforces consumer protection measures and antitrust legislation. Its seats are typically comprised of three members of the president's party and two from the opposing party.