Sessions v. Dimaya

Vague laws invite arbitrary power. Before the Revolution, the crime of treason in English law was so capaciously construed that the mere expression of disfavored opinions could invite transportation or death. The founders cited the crown's abuse of "pretended" crimes like this as one of their reasons for revolution. See Declaration of Independence ¶ 21. Today's vague laws may not be as invidious, but they can invite the exercise of arbitrary *1224power all the same-by leaving the people in the dark about what the law demands and allowing prosecutors and courts to make it up.

The law before us today…