Well the conservative argument, as opposed to the libertarian one, is that society can't afford to grant people freedom, if they are going to act irresponsibily, so you need to keep stuff outlawed that will put a really bad burden on society.  The libertarian argument is actually to grant maximum freedom, and contain the consequences to individuals only, if possible.  In cases where groups of people get affected by others, in ways that is hard to trace to an individual specifically, that is just the price of freedom.  In all cases, markets manage to sort things out anywhere.  All you need is a proper price mechanism to account for these.  Oh, there is also the use of courts to sue individuals, which is a Libertarian solution for polution.  If a person feels that their rights to good air are infringed upon, they have a right to sue a factory poluting and win a settlement against them.

The problem with the conservative argument is that it can be applied to anything and it often is. For example, conservatives are trying to act like gay marriage will destroy society, but in reality when that right is given out nothing will really change.

In this case, I side with the Libertarians, people should have maximum freedom on most social things. If someone wants to smoke weed, let them. Why arrest them for that? when they are only really harming themselves. It's their choice. I think it's only a crime when others are physically hurt or killed in some way. I find the conservative argument to things like this, very contradictory. They think drugs like weed are so bad that people should be arrested for it and yet a little a gun reform and they all turn against it. They believe in no restrictions for gun ownership at all, and yet they carry the same individual risk and responsibility that smoking a drug like weed does.

The only problem i see with Libertarianism is where does freedom end. Some people might see discrimination as a right, although it is morally wrong. While, a factory owner might think it's his right to dump his waste as cheaply as possible by pouring it into the river, which affects others rights to clean water and possibly food too. At this point, Government regulation is necessary.