AP Photo/Susan Walsh Cornell Woolridge of Windsor Mill, Md., takes part in a demonstration outside the Supreme Court in Washington, Tuesday, Oct. 8, 2013, as the court heard arguments on campaign finance. O ver the past few years, given the bad news that just keeps coming their way, America’s campaign-finance reformers have started to look like eternal optimists. They’ve pretty much had to be. Take the one-two wallop they suffered early this spring. First, Governor Andrew Cuomo and New York state legislators killed reformers’ best chance of a breakthrough in 2014—a public-financing program in which small-dollar donations would be matched or multiplied by public funds. (New York City already runs its own “matching” program.) The idea was to give less-wealthy donors a bigger voice in legislative and gubernatorial races while decreasing the clout of those with deep pockets. Instead, reformers ended up with a microscopic pilot program for the state comptroller’s race. A few days later...

D uring the brief time in the election cycle when the voting booths are actually open, we hear a lot how smoothly elections are going—where voters are waiting in long lines, where ballots are getting rejected, and the like. Elections expert Doug Chapin, who heads the University of Minnesota’s Elections Academy, calls it “anec-data”—anecdotes substituting for hard numbers. In a presidential election, we tend to hear all about problems in swing states, since the national press corps is already there, but we’re less likely to hear about issues in Montana or Connecticut, where the election outcome is almost a foregone conclusion. Good data would make it easy to compare states’ election performance, and more importantly, let us see how states are improving or declining from one election to the next. That’s why Pew’s 2012 Elections Performance Index is a big deal. Released this week, the index uses standardized data from the U.S. Census, the Elections Assistance Commission, and a major...