On Oct. 3, two weeks after the first Occupy Wall Street squatter settled on a marble bench in Zuccotti Park, most of the nation's liberal kingpins gathered 200 miles away in Washington to voice their solidarity. "Let the word go forth," called a speaker on the ballroom stage at the Washington Hilton. "They got unity on Wall Street. They got unity in 50-some cities. And we've got unity in this room."
It was a remarkable gamble: hundreds of student, environmental, labor, feminist, immigrant and minority-rights leaders pledging support for a cause they neither foresaw nor controlled. Even more remarkable was the...