A new poll from San Francisco's Field Research Corporation shows support for gay marriage in the state surpassing 60 percent for the first time. Since 1977, public opinion on the topic has shifted 60 percentage points, from 28-59 against to 61-32 for. Graphed, it looks like this.

What's interesting about this graph is that little wrinkle in 2008, that little burst where the red bar goes back up, briefly. That's the November 2008 vote on Proposition 8, which broke with the on-going pattern of declining opposition. Currently, the constitutionality of Prop. 8 is being considered by the Supreme Court as the president and Congress speak out against the measure. But it seems clear that the people of California, the same ones who passed Prop. 8 in the first place, have already made up its mind.

It's also remarkable how significant the timing for the measure was: shortly before the vote was held, same-sex marriage for the first time enjoyed a majority of support in the state. It may quite literally have been the last chance for opponents to win on the issue.

If public support topped 50 percent, why'd Prop 8 pass? The voting electorate doesn't always represent everyone in a state, of course, and voting populations tend to skew older and more conservative. As Field's new poll indicates, it's among older Californians that same-sex marriage fares the worst. 48 percent of people 65 or older approve of the practice, compared with 78 percent of those under 40.

This raises another question: If support for gay marriage is so high, why not hold another vote and override Prop 8? The answer to this resides with the Supreme Court. Supporters of same-sex marriage hope that the measure's arrival at the Supreme Court will obviate the need for California -- or any state -- to declare same-sex marriage legal. A finding from the court that bans on gay marriage are unconstitutional makes invalidates Prop 8 by itself, as well as setting the law of the land broadly.

In other words, for supporters of same-sex marriage in California, the important voting numbers aren't 61 percent for to 32 percent against. What's important is how many votes they can get out of nine people sitting in Washington, D.C. The vote will be close, and, once again, it will skew older and more conservative.