There is a distinction between affirming someone or some organization has a power and affirming it can be morally exercised. The recent change in the catechism did not say states didn’t have the power, only in present circumstances, there was no moral time it could be exercised.

I explain this more in this article: see the section “Permission to a Power.” http://www.patheos.com/blogs/throughcatholiclenses/2018/08/capital-punishment-francis-the-tradition-are-both-right/