Reading over the various posts and comments, I think I'm beginning to understand the argument Maggie is making. The argument is that extending marriage to include same-sex couples would not just give rights to a small subset of the population, but would radically transform what marriage is. So long as only opposite-sex couples can marry, the thinking goes, marriage is linked to procreation; if same-sex couples can marry, too, then marriage is transformed into something else entirely. Adding same-sex marriage would ruin the old institution and create a new one, and the new institution would not longer retain a focus on having and raising children. Viewed in that light, same sex marriage is a threat to society: by redefining the institution, it will kill off its most important feature.

  Leaving aside the question of whether this argument is persuasive, am I at least understanding it accurately?