Morally Guided Laws?

I know that this is not a small topic to breach, and that we have partially discussed it before, but I would like to hear some thoughts on what the class believes when it comes to making laws based on moral laws. This is a topic I have struggled with for sometime. I think there are certain things that the government needs to mandate out of self-preservation. Making murder, any other kind of severe physical abuse and treason illegal would fall under this category in my mind. The thing that catches me is whether our government should really base laws or build social programs based on moral laws or what is "fair".

Extreme examples, in my mind, would be things like gay marriage, abortion, the welfare system and the tax policy that is being put in place in a few months. (a side-note: we don't have time to discuss these specific examples and I do not think permanently publishing the class' views on abortion or gay marriage would be a great idea, I am just using them as examples.) When I look at laws based on the question of whether something is fair or not, I see a lot of failed programs which might not have been have been based in logic to begin with. Taking the upcoming tax policies as an example, the laffer curve (as well as the last Great Depression) shows us that raising taxes both stunts the economy and lowers the national tax revenue. Is further damaging an already broken economy while further bankrupting our nation, worth aiding people who do not 'contribute'* to the economy? The problem with this is that many people don't believe this is a 'fair' practice anyways, ignoring the likely consequences. Seeing as there is no solid definition for something being 'fair', there is no solid defense for these policies.

This can then be applied to other social policies. How can you prove that something is moral? Ethics have been heatedly debated for thousands of years, and now we force people to adhere to the 'moral codes' of Washington? Do you trust the morals of Washington? I don't.

*When I say 'contribute' I mean that they pay taxes. I am referring to President Elect Obama's plan to give tax refunds to members of our society who do not pay taxes to begin with.