1. This is the chart everyone knows by now. Public opinion has moved strongly in favor of legalizing gay marriage over the last decade. And -- breaking news here -- politicians tend to do what they think the public wants them to do.
2. It's not just that opinions are shifting on gay marriage but how they are shifting that matters. Support and opposition are split far more on generational lines than on partisan ones. Among self-identified Republicans aged 18-49 in the most recent Washington Post-ABC News poll, a majority -- yes, majority -- said same sex marriage should be legal. Compare that to just 25 percent of Republicans aged 65 or older who feel the same way and you see that on this issue it's not about "D" or "R" as much as it is about the year you were born.
3. And, while young people are the most supportive of gay marriage -- eight in ten in the most recent Post-ABC survey -- every generation is growing more accepting of the idea as they age. That's a critically important finding since it suggests that as young people age -- and as middle age people grow older -- they don't reverse course and become less supportive of the idea of gay people being married.