President Donald Trump's personal lawyer Jay Sekulow said on Sunday that the U.S. Supreme Court may ultimately be called on to decide the scope of presidential pardon power.

If that happens, the justices will likely dust off one of the few cases in which the high court has ruled on the pardon power: the 1866 decision in Ex Parte Garland, involving one of the most prolific—and acerbic—advocates before the court: Augustus Garland.

The Garland ruling, already cited in recent articles about the pardon issue, stated, “The power of pardon conferred by the Constitution upon the President is unlimited except in cases of impeachment. It extends to every offence known to the law, and may be exercised at any time after its commission, either before legal proceedings are taken or during their pendency, or after conviction and judgment.”