what provisions would you use would you invoke if you wished to attack constitutionally of the death penalty?

Answer 1

the inaliable right to life (liberty, and pursuit of happiness)

Answer 2

At the time the Constitution was written, capital punishment was in common use around the world. The Founders of the US would have had no reason to deal specifically with the death penalty. There weren't any bleeding heart, left wing loonies around to bellyache about capital punishment. Many crimes, such as horse thievery, were punishable by death. Now, if someone steals a horse, his punishment might be no more than a slap on the wrist.