Many economic conservatives, libertarians think that social issues aren't important, more a nuisance than anything else. In fact, nothing could be further from the truth. Strong marriages and families are a prerequisite for limited government. Why? Because when marriages and families breakup, a host of social problems result, e.g. higher poverty rates, crime, education and personal problems, etc. And government is invariably called upon to fill the gap. And that means higher taxes and more government programs and regulations and dependency.
Dr. Jennifer Roback Morse, an economist and President of the Ruth Institute makes this case in a couple of articles. One was printed by the Heritage Foundation here and the other by National Organization for Marriage here.
So the next time your libertarian friend says redefinition of marriage and marriage breakdown are unimportant, you'll have some good responses.