The New York hush money trial against Donald Trump is entering day 18 of the historic first criminal proceedings against a former president, but legal experts say prosecutors have yet to identify the “other crime” needed to upgrade misdemeanor charges to a felony conviction.

Trump’s former attorney and fixer Michael Cohen is set to take the witness stand again Thursday for his second day of cross-examination by the former president’s defense team. The trial has pushed forward at a steady pace and is ahead of schedule, yet prosecutors have left a glaring hole in their argument that Trump is guilty of 34 felony counts of business record falsifications in the first degree.