As we've learned what works and what doesn't, constitutions have started to look and more alike. Not surprisingly, the U.S. has one of the world's least generic constitutions. (Djibouti has the most.) American exceptionalism is a fine thing, but there are still things we can learn from other places. "The Founders had only impressionistic, sometimes wrong, assumptions about human behavior," says Ryan Enos, a political scientist at Harvard. "We know a great deal more now, due to advances in psychology and other fields, about the nature of cooperation, group identities, incentives, et cetera."
Take elections, the most basic function of any democracy. We've been doing them the same way since the Progressive era, but instant-runoff voting has become increasingly popular because it allows voters to rank multiple choices instead of picking just one. Australia, India, Ireland, and dozens of other countries have adopted it, as has San Francisco and the Academy Awards. IRV, as it's known, would make room for new parties by allowing people to vote for a third-party candidate first without "wasting" it, and then for a mainstream candidate second. This change would force politicians to compete for everyone's votes, because they would need non-first-choice votes too. Alternately, we could also eliminate party primaries, as California did recently, and replace them with a nonpartisan runoff between the top two vote-getters. These innovations would help reduce one-party monopoly and avoid the radicalizing effects of partisan primaries.