What is unprecedented about the Department of Justice's effort to drop corruption charges against New York City Mayor Eric Adams?

The Department of Justice is attempting to drop corruption charges against Eric Adams based on political motivations rather than traditional legal reasoning. Their argument centers on the president wanting Adams' help with border security policies in New York City. This approach is unprecedented because cases are typically dismissed due to shifting facts or legal issues, not political considerations. As Scott McFarlane notes, this is 'a pure political motive' for dropping criminal charges, creating a complex situation for the judge who must unwind this unusual legal maneuver.