" In 1960, just 5 percent of Republicans and 4 percent of Democrats said that they would feel “displeased” if their child married outside their political party.5 By 2010, those numbers had reached 49 and 33 percent, respectively—far higher than the percentage of people who would be “displeased” if their child married someone with a different skin color. "

― Cass R. Sunstein , #republic: Divided Democracy in the Age of Social Media