James Cooper, 46, crashed into a Secret Service vehicle as the president was exiting an event at his campaign headquarters in Wilmington on Sunday, the police said.
Judge Maryellen Noreika sent the two sides back to try to work out modifications that would address her legal and constitutional concerns and salvage the basic contours of the agreement.
The president’s son is scheduled to appear in Federal District Court in Wilmington to plead guilty to two misdemeanor tax charges and accept an agreement that would avert prosecution on a gun charge.