There’s a long-running debate among public mentators concerning the prudence of pursuing an all-or-nothing agenda or moving incrementally toward a particular goal.

How much modation is wise if that modation does make movement, however small, towards an ideal state of affairs, and yet also reinforces a system that is structurally opposed to the ultimate realization of that same ideal? When is it politically prudent to let the perfect potentially be the enemy of the good?

These questions in the context of all sorts of policy issues, but some examples include the libertarian concern to move toward a minimal or non-existent state, the pro-life concern to make abortion non-existent, and the gay “marriage” concern to legitimize and legalize same-sex partnerships.

The past week has seen a significant victory in this third arena in the state of California. When the state supreme court validated the practice of legal recognition of same-sex “marriage,” it cited the long history of the state government recognizing similar rights, privileges, and responsibilities for same-sex couples. That is, the incrementalist same-sex marriage approach, which sought sanction for same-sex adoption, same-sex partner health benefits, and so on, paved the way for the courts to recognize same-sex “marriage” as the last in a discernible line of logical public policy progression.

Citing a long list of moves by the state legislature to “equalize” treatment of same-sex couples (PDF of decision here, summary here), the majority concluded that “the current California statutory provisions generally afford same-sex couples the opportunity to enter into a domestic partnership and thereby obtain virtually all of the benefits and responsibilities afforded by California law to married opposite-sex couples.”

The perfectionist argument has been often based on a sort of Zeno’s paradox for public policy: modation or incrementalism may improve the state of affairs, but it likewise removes the possibility of achieving total victory. At least in the case of California and same-sex partnerships, that paradox seems to have been resolved in favor of the incrementalist approach.