The Supreme Court will hear arguments today on whether the president can fire board members of independent agencies at will, challenging a 90-year-old precedent.

Chief Justice John Roberts has led the Supreme Court 's conservative majority on a steady march of increasing the power of the presidency, starting well before Donald Trump's time in the White House.

Monday’s case specifically tests whether President Trump can fire Rebecca Slaughter, a Democratic member of the Federal Trade Commission, simply because he says she does not align with his agenda — de...