When predicting the future of gay marriage around the world, it's tough to argue with the numbers: Nate Silver points out that Argentina's decision to sanction it means that 250 million people now live in places where it's legal. Click through to see his chart at FiveThirtyEight.com, which shows the steady rise of that number since the start of the decade.
"Right now, it's possible to marry your same-sex partner in Buenos Aires, in Mexico City, in Ames, Iowa, and in Pretoria, South Africa, but not in San Francisco," he writes. "With countries like Argentina and Portugal now recognizing same-sex marriages, however, the global trajectory has returned to its slow-but-steady upward pace." (Read more gay rights stories.)