Why isn’t the death penalty included in your “Voter’s Guide for Serious Catholics”? Look at the last paragraph of no. 2267 of the Catechism.
The death penalty did not make the list because it does not involve something intrinsically evil. If that were the case, then the Church would not permit recourse to the death penalty under any circumstances. Instead, we read in the Catechism the following:
The traditional teaching of the Church does not exclude, presupposing full ascertainment of the identity and responsibility of the offender, recourse to the death penalty, when this is the only practicable way to defend the lives of human beings effectively against the aggressor.
If, instead, bloodless means are sufficient to defend against the aggressor and to protect the safety of persons, public authority should limit itself to such means, because they better correspond to the concrete conditions of the common good and are more in conformity to the dignity of the human person.
Today, in fact, given the means at the state’s disposal to effectively repress crime by rendering inoffensive the one who has committed it, without depriving him definitively of the possibility of redeeming himself, cases of absolute necessity for suppression of the offender today . . . are very rare, if not practically non-existent. (CCC 2267)
The statement that recourse to the death penalty today should be “very rare, if not practically non-existent,” is a matter of prudential judgment (cf. Evangelium Vitae 56).