The legal institutions of a democratic and capitalist society are designed not to give people what is good and prevent them from getting what is bad; they are designed to give people what they want and not give them what they don’t want.
The fundamental problem with the mandate is that it coerces some people into doing what they think is wrong, and this problem remains regardless of whether the coercion excuses the actions of the people being coerced.
A eudaimonistic ethical theory can show, without appeal to God, that certain actions are always wrong.
Divine legislation functions to enforce moral absolutes, not to ground them.
Aristotelian virtue ethics has very little to say about what is a good political structure or economic system.