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

Justice is the first virtue of social institutions, as truth is of systems of thought. A theory however elegant and economical must be rejected or revised if it is untrue; likewise laws and institutions no matter how efficient and well-arranged must be reformed or abolished if they are unjust.

Political philosophy is realistically utopian when it extends what are ordinarily thought to be the limits of practicable political possibility and, in so doing, reconciles us to our political and social condition. Our hope for the future of our society rests on the belief that the social world allows a reasonably just Society of Peoples.

An intuitionist conception of justice is, one might say, but half a conception.

Clearly when the liberties are left unrestricted they collide with one another.

The perspective of eternity is not a perspective from a certain place beyond the world, nor the point of view of a transcendent being; rather it is a certain form of thought and feeling that rational persons can adopt within the world ... Purity of heart, if one could attain it, would be to see clearly and to act with grace and self-command from this point of view.

What's important is that people give the kinds of reasons that can be understood and appraised apart from their particular comprehensive doctrines: for example, that they argue against physician-assisted suicide not just by speculating about God's wrath or the afterlife, but by talking about what they see as assisted suicide's potential injustices.