Justice Samuel Alito grilled Federal Reserve governor Lisa Cook’s lawyer over what would be a sufficient reason for a president to remove someone from the central bank, including whether past support of Adolf Hitler would qualify.

The Supreme Court heard arguments on Wednesday in the emergency docket case Trump v. Cook, evaluating whether to allow Cook to be fired or reinstated while her lawsuit challenging her purported firing “for cause” continues to work its way through lower federal courts. The justices were skeptical of Solicitor General D. John Sauer’s arguments for allowing Trump to fire Cook, but they also expressed concern over arguments by Paul Clement, Cook’s lawyer, limiting the scope of what could be considered “cause” to remove a Fed officer.