One common response to the district judge's decision in the Same Sex Marriage Ruling is that it is significant that he relied as much as possible on factual findings. Such factual findings are supposed to be given deference by appellate courts -- clearly erroneous review -- and therefore the Supreme Court, if it is being honest, which it may not be, should grant such deference and probably affirm his decision.
On one level, this seems like a correct argument. Yet, there is something of a problem about it: If one believes that the Supreme Court's affirmance of the decision would function like other big cases, such as Roe v. Wade or Lawrence v. Texas, to decide the issue for the country, then it would be odd that a single district judges would have had so much power.
What gives? I believe the resolution is as follows. If we treat the district judge's factual findings as entitled to deference, then they should have no effect in future cases. So imagine that the Supreme Court affirms the California case. The next year a federal district court in Texas hears a similar case about their law limiting marriage to traditional marriages. The court reaches different factual findings and concludes that the law is constitutional. If the Supreme Court gives deference to this court's factual findings, it ends up concluding that the law is constitutional.
The reason for these differing results is that the Supreme Court decision is not really deciding the full case of gay marriage. It is instead deciding whether the district judge applied the law correctly to the facts decided by the district judge. And there is no obligation for a future district judge to follow an earlier district judge's factual findings.
In fact, if another lawsuit is brought in California involving different parties -- say between a different private party and an institution other than the state of California who had an interest in Proposition 8 applying -- that district judge could reach different facts that the current district judge in California and that would be affirmed by the Supreme Court as well.
What is the upshot of all this? The current meme out there -- that the district court decision's will make it harder for the Supreme Court to not reach a broad decision in favor of gay marriage -- is misleading. Either the Supreme Court will give deference, in which case it will reach an extremely narrow decision that does not apply to other parties. Or the Supreme Court will not give deference, and decide it on broader grounds which will have effect throughout the country. In the latter case, though, there would not be deference to the factual findings of the district court.