in 1972, did the Supreme Court rule that the death penalty was unconstitutional?

Answer 1

It's a bit more complicated than that. In the 1972 case Furman v. Georgia, the Court struck down death penalty laws not on the grounds that all executions were inherently unconstitutional, but primarily on the grounds that death sentences were imposed inconsistently. It was not the penalty itself, but rather the relative arbitrariness with which the penalty was inflicted, that was found to be "cruel and unusual" in violation of the 8th Amendment. Many states subsequently passed new death penalty laws, some of which the Court upheld.

Answer 2

if they had why do most states still allow it?