There is a current in libertarianism that welcomes expansion of federal power, as long as this promoted “personal freedom”. Such sentiments are all right, provided that a) “personal freedom” means the same thing to me as it does to you, and b) that expanded federal power can’t later on be used to take away personal freedoms. Unfortunately, neither of the two are always the case, and often they are the opposite.
Exhibit A: gay marriage. Recently the Supreme Court decided that marriage was a fundamental right that could not be denied on the grounds of the sex of the consenting parties. At first glance, this looks like a victory for personal freedom. On further consideration, it does nothing to change the fact that the government still has a say in who you can legally marry, e.g. if you’re already married to another person, you’re not allowed to marry a third person, even if your current spouse consents. Some libertarians have pointed out how government continues to regulate our private lives through licensing marriage, but many others have ignored this fact in order to cheer on this enormous new expansion of federal power. And this ignores the other consequences for personal liberties that accompanied this decision, e.g. the lawsuits brought against business owners that refuse to cater to gay couples on the grounds that this violates the public accommodations clause of the Civil Rights act. An extension of personal liberty in one area is accompanied by a retraction of liberty in another, owing to our messed up legal system.
The solution I prefer is for the federal government to get out of marriage completely. This would give powers back to the states to ban gay marriage, but I think I part ways with many libertarians on things like social legislation. Societies and communities differ in their values and norms and it is reasonable for each community to wish to regulate itself in a way that it sees fit, even if that means tolerating something less than libertarian at the local level. I think I would draw the line at civil rights, however: states should not be allowed to deny local residents the rights enumerated in the Bill of Rights, for example, such as right to fair and speedy trial. I need to think more about what powers should be given to the states and what powers should be withheld, but at first approximation I would say the line should be drawn at the Bill of Rights.