It's been pretty quiet on the same-sex marriage front since California voters approved Proposition 8 last November. But that could all change tomorrow, when the Iowa Supreme Court is expected to rule on a constitutional challenge to the state's statutory same-sex marriage ban.

As explained by Jason Hancock at the Washington Independent's blog, this is a straightforward equal protection/due process challenge based on the state constitution. It's not that different from the challenge that temporarily succeeded in Massachussets a while back.

What makes the Iowa situation significant is that it's in, well, Iowa, far from the coastal areas where same-sex marriage disputes have most often raged. If the plaintiffs win in Iowa, you can expect conservatives to mount a constitutional amendment effort, but that's failed repeatedly in the state.

Expect tomorrow's ruling, whichever way it goes, to reverberate for quite some time.