Answer for Susan

Elizabeth Brown’s answer to Susan’s question sums up my reasons eloquently.  I am not necessarily advocating for an “Intimate Partnership Act,” but I do think there are good reasons for society to promote such bonds.  When I said, it is "irrelevant to the state as to why someone would want to form such an association," what I had in mind was an analogy to the law of charitable deductions. 

The charitable deduction imposes costs on society, including the cost of less tax revenue.  The imposition of those costs is justified by the desire to promote a certain type of giving.  But, it is irrelevant to the state why someone forms a non-profit organization or why someone gives to organization “A” rather than organization “B.” In short, the community has decided that promoting charitable giving by privileging such expenditures is in the common good.  Employing principles of subsidiarity, the community allows individuals to form their own charitable organizations and to decide which, if any, organizations will receive their money.  The same rationale could be employed with respect to state promotion of friendships; the state provides a broad form, leaving individuals free to decide whether to seek the benefits and burdens that this form of friendship entails.