In a time like ours, one of the fundamental distinctions we must master is the distinction between a sin and a crime. This is more complicated than it looks or sounds. A crime is something outlawed by the civil authorities, and in what they have done, they may have behaved wisely or foolishly. For example, sometimes they outlaw things that biblical law would also outlaw (e.g. murder), sometimes they outlaw things that the Bible defines as sin but not as criminal (e.g. hatred), and other times they outlaw things that the Bible defines as righteousness (e.g. disapproval of sodomy).
The one thing we must banish from our minds is the idea that legality defines righteousness. It does not. A legal divorce can be wicked before God, for example. And at the same time, we must banish the idea that many Christians have that if something is sinful in the eyes of God that there ought therefore to be a law against it. This is absurd also. Covetousness is a great sin, but it cannot be made illegal.
The way we should navigate this is by remembering that as Christians we always answer to God and His Scriptures in the first instance. If any conflict ever arises between a course of action required by the Word and a course of action required by the magistrate, we must always obey God rather than men.
The first step in doing this is to be severe on your own sin first. One of the reasons why we have such bizarre moralistic crusades in the public square is that individuals refuse to mortify their own sin first. We would always rather start with our neighbor. But this edifying procedure must be rejected every time the tempter suggests it to you.
So the first step in distinguishing sins from crimes is the honest process of confessing your own sins to God, fully, completely, and without guile.