There is no one man more responsible for this than Karl Rove. If he hadn't used what was essentially a fringe issue to stoke fear ahead of the 2004 election, same sex marriage would never have advanced as rapidly in the US as it did. He focused the efforts of campaigners in favour of it, but moreso, he had people talking about the issue and engaging with it over their dinner tables a decade ago. And in that time, no argument against it has stood up. As less and less people accept "I just don't like it", full nation-wide legalisation became inevitable, and while it's a shame it took the courts to do it, it was always on it's way... and while he wasn't the main reason, Karl Rove deserves more credit than any other individual for it, I think.
The fact that statistically speaking it didn't do anything for the election either is also some great poetic justice.
