FOR two decades, American voters have hankered to proclaim themselves Independent, even as the two mainstream parties have felt little risk of being pushed aside. Indeed, Michael Bloomberg—who was a Democrat until he ran for office as mayor of New York in 2001, then a Republican from 2001 to 2007 and now considers himself an Independent—explored the idea of running for president as an Independent only to conclude it was folly. But a survey today from Gallup shows the astounding degree to which Americans are losing interest in classic party affiliations.

A record 42% of people consider themselves Independent, compared to Democrat (31%) or Republican (25%). That's a huge shift from just a decade ago, when affiliations were divided around a third for each. The chart below shows how Americans' dissatisfaction with the parties is nothing new. (Note the surge in independents around the time of Ross Perot's 1992 presidential campaign.) The spike in Independents is eating more into the GOP, which has seen party moderates sidelined by extremists. The data suggest that there may be a place for a Bloomberg presidential bid after all.