When H.L.A. Hart began developing his theory of law, he insisted on placing it in a social context. This is a useful starting point; I think it will lead us down a path that will help us deal with the various contentious issues of the day.
For the sake of brevity, when I say the Law, with a capital "L," I mean a formal legal system as a whole. Lower case "l" is just an individual law.
Since this is a philosophy of law, it needs to be rooted in a particular conception of humans. I'll only sketch this out here, and will write more fully in a later post.
There are two common ways of thinking about the Law that I'm opposed to. The first is the Social Contract Theory (SCT) as concieved by either Hobbes or Locke. Basically, we all agree to not kill each other so we can engage in economic pursuits. The second is the "harm principle" as concieved by JS Mills. The Law exists to keep us from hurting each other, and has no other purpose.
Both of these ideas have an atomistic view of humans - we're all individuals, and we develop our lives in a solitary way. We can satisfy our desires without the aid of others, though others can inhibit our satisfactions. The Law prevents this inhibition.
I think it's more accurate to speak of "intersubjectivity." There are facits of our being that we can only explore and develop when engaged with other humans, and the word in general. We aren't solitary; our skulls aren't bunkers protecting our minds as we peer out at the world from the gunports of our eyes. We interact with the world and other humans.
This interaction is governed by the desire for recognition; we want to see that others desire us, and we want to affect the world. An ideal world is one big mirror, and that's what we constantly try to do; make the world mirror ourselves back to us.
One facit (certainly not the only) of this is that we want to have power over others. This power can come in the form of influencing individual behaviour - to have another person follow your commands. This also works on a more general level; we want those around us to recognize our behaviours and ideas as worthy. On a gut level, we believe the ideal expression of this power is that others act and think increasingly like us.
So here is the birth of Law: increasing our own influence and power in the world. Engineering the world to make it one big mirror. The inevitable danger here, of course, is totalitarianism. That's power run amok - making bloody well certain everyone is just like you. This is also the power of democracy; it creates an enviroment in which people compete for recognition without coercion. Democratic societies also most effectively nurtures other forms of the desire for recognition; art and work, as two examples.
This is why one of the insights of the Critical Legal theorists is so useful: the settled law is a temporary truce in an ideological war. A law is codified because an individual or group felt it was something that needed to be imposed on the whole of society. The Law is inherently political.
As an example, when anti-SSMers complain about being forced to recognize SSM, they're right. The question is, does the SSM law contribute to an increasingly democratic society, or a totalitarian society?
The political spectrum, on an average day, looks like a straight line. On one end you have totalitarianism and mutual extermination, and on the other end you have democracy. But it's not a straight line - it's a circle. Think of it like this; standing where you are now, it's far from obvious that the Earth is a sphere. You have to travel a great distance to gain a sense of roundness. And it's the same on the political spectrum - follow any political ideology too far, and you'll come back around to totalitarianism.
So that's why the basic question of any law is "is it democratic or totalitarian?" Does this law further enable people to pursue their desires, or does it force them to come in line with your own desires? The easy impulse is towards totalitarianism - it's like junk food. Only carefully considered and responsible laws can foster democracy - a healthy diet.