There are two ways to defend gay marriage. Argument A is empathy: One is influenced by gay friends in committed relationships yearning for the fulfillment and acceptance that marriage conveys upon heterosexuals. That’s essentially the case President Obama made when he first announced his change of views.
No talk about rights, just human fellow feeling. Such an argument is attractive because it can be compelling without being compulsory. Many people, feeling the weight of this longing among their gay friends, are willing to redefine marriage for the sake of simple human sympathy.
At the same time, however, one can sympathize with others who feel great trepidation at the radical transformation of the most fundamental of social institutions, one that, until yesterday, was heterosexual in all societies in all places at all times.