In 2008, a majority of the Supreme Court decided that executing a man who raped his eight-year-old stepdaughter so violently that she required emergency surgery violated the Constitution’s prohibition on cruel and unusual punishment. That’s the holding of Kennedy v. Louisiana, 554 U.S. 407. Four justices disagreed. Sixteen years later, multiple states have passed laws saying the majority was wrong and they intend to prove it.

The majority opinion, written by Justice Anthony Kennedy — a different Kennedy than the defendant, which the press found reliably confusing — rested on the “evolving standards of decency” framework the court has used since Trop v. Dulles (1958). The test runs in two steps: first, count states and look for a national consensus; second, apply the court’s own independent judgment about proportionality. Kennedy did both and concluded that the death penalty for child rape, where the victim survived, was categorically off the table.