A Bad Day for the Presidency

The Supreme Court looks like it was trying to split the baby Thursday in a pair of 7-2 decisions on subpoenas for President Trump’s personal records. But forget about Mr. Trump. The real import of the rulings is that the Supreme Court has weakened the Presidency by opening the gates to harassment by Congress and especially local prosecutors.

As a practical matter, the Justices remanded both cases to lower courts to reconsider based on new general guidelines laid out by the majority opinions. This means Mr. Trump probably…