The problem is that gov't FORCES everything on everybody; markets allow each to choose what is important to them. A really good example of the conflict is the current health care debates - if you want to see both sides in close argument, look at the comments on Megan McArdle's blog at The Atlantic. Megan claims to be a libertarian, but she's not much of one, I follow her blog mainly because of the interesting conflict in the comments.

Also, I am serious about does anyone have any rational justification for gov't other than its ability to threaten.