Michael Cook has attempted, in a somewhat worthy fashion, to analyze why the contemporary marriage debate has yielded so little understanding. See "Why does the same-sex marriage debate seem so futile?"
His classification of the marriage culture into "legal" and "tabloid" strikes me as a tad thin. Authentic Catholic marriage culture sees marriage as a covenant oriented in a natural way to fecundity and raising children (even when physical fecundity itself is long gone). As such it is inherently heterosexual, self-donating and life-long. The stability and fruitfulness of the marriage covenant as a human institution is essential to the stability and fruitfulness of civilization itself. Because of this, marriage law is oriented properly to marriage, not vice versa.
Post-modern marriage is something entirely different, indeed so different we probably shouldn't even call it marriage, and continuing to use the same term without distinction is the primary reason we have come to this political impasse. Gays and lesbians interpret Catholic attempts to protect Catholic marriage as excluding them from access to the post-modern institution. Catholics themselves generally fail to grasp the fact that the argument over the meaning of marriage is already substantially lost in the culture, and "non-partisans," who don't generally know what to think, most frequently "opt" for "gay marriage" because they don't like to see emotional suffering.
It is as if we have forgotten the mathematical definition of pi, can no longer retrieve it from history and now find ourselves embroiled in pointless arguments about its numeric value. Meanwhile (to continue the analogy), the advanced tehcnological culture that was built on a clear mathematical definition of pi is crumbling beneath us.