There are various ways you might define the common good, but that would be one way you could do it.

We must choose for others as we have reason to believe they would choose for themselves if they were at the age of reason and deciding rationally.

It is of first importance that the military be subordinate to civilian government

A comprehensive doctrine, either religious or secular, aspires to cover all of life. I mean, if it's a religious doctrine, it talks about our relation to God and the universe; it has an ordering of all the virtues, not only political virtues but moral virtues as well, including the virtues of private life, and the rest. Now we may feel philosophically that it doesn't really cover everything, but it aims to cover everything, and a secular doctrine does also.

Citizens can have their own grounding in their comprehensive doctrines, whatever they happen to be.

Properly understood, then, the desire to act justly derives in part from the desire to express most fully what we are or can be, namely free and equal rational beings with the liberty to choose.

People can make arguments from the Bible if they want to. But I want them to see that they should also give arguments that all reasonable citizens might agree to.