So the court battle begins already. As harlkyn posted in his LJ, civil rights groups have already filed a lawsuit claiming that the proposition isn't merely an amendment, but fundamentally changes the state constitution, which is a no-no if it violates existing rights. Since the California Supreme Court has already ruled previous laws violated those rights, it seems like (hopefully) a 'natch. It's a shame this has to happen in the courts, but that's pretty much how it's always been expected to go down.
Then again, I rather like sftyson's idea - since the argument is that the 'mos are ruining marriage, we should propose a few amendments to outlaw the REAL culprits. How about making divorce illegal? That fucks up more families than a few thousand queers, right? Or maybe adultery should be prosecuted a bit more harshly? In fact, I think we should require marriage licenses be more like the bar exam or medical boards - people should study and test and get trained. After all, that would save more marriages, wouldn't it? :)