I think its possible, and I might consider such it preferable, but for it to be done right it would have to come as an advancement in common law. So if not having the death penalty was established throughout the land on say, a state by state basis, and it enjoyed widespread public support in those areas, and the logic and moral frameworks were robust enough to withstand criticisms, then it would be so.

As it stands, this isn't the case, many consider the death penalty to be right, and they have formidable arguments in its favor. I don't agree, I am not a fan of the death penalty, but I am against imposing a ban without establishing it as common law first.