The editors of the Nation, for instance, support gay marriage but do not usually defend the sanctity of contracts. This apparent paradox evaporates when we realize that the dissolution of marriage breaks the family into successively smaller units that are less able to sustain themselves without state assistance.The basic idea here is that by dissolving marriage, it puts a greater dependancy on the state. Or put another way, if you want to create and support a large central government, one way to accomplish that is to dissolve any meaning behind marriage. The resulting society will be much more dependant on the state for resolution of even trivial disputes. Disputes that are less intrusively resolved in an organic marriage.
The modern claim that there need not be and should not be any social or legal preference among sexual or childrearing contexts is, by definition, the abolition of marriage as an institution. This will be a disaster for the cause of limited government. Disputes that could be settled by custom will have to be settled in court. Support that could be provided by a stable family must be provided by taxpayers. Standards of good conduct that could be enforced informally must be enforced by law.This is a very interesting premise that the author (Jennifer Roback Morse) does a good job of explaining. I highly recommend reading the whole thing.
My vote for the most insiteful comment:
An appreciation of voluntary cooperation between men and women, young and old, weak and strong, so natural to libertarians and economists, is completely absent from this statist worldview.
This is why it is no accident that the advocates of sexual laissez-faire are the most vociferous opponents of economic laissez-faire.