We need a federal government to do about 10% of what it is currently doing. Let the individual, sovereign states decide what they wish to do, and let the people do the rest.
Government is the problem, not the solution.
10% of gigantic is still a sh!tpot of power!
Congress has 18 enunerated powers under Article 1. The post office is not an optional duty. It is specific ad precise. There is no dicussion about this.
Sorry clear, just re-read article 1. Congress has the power to post offices which you are right, it is not mandated.