A fter years spent fruitlessly attempting to organize Wal-Mart, unions and other liberal activist groups have taken a new tack: a public campaign to force the Bentonville behemoth to become more socially responsible. In 2005, Andrew Stern, the president of the Service Employees International Union (SEIU), created Wal-Mart Watch, with an annual budget of $5 million, devoted exclusively to making Wal-Mart "a better employer, neighbor, and corporate citizen."At almost the exact same time, a parallel group called Wake Up Wal-Mart launched, with much the same goal.

In the nearly two years since, both Wal-Mart and its new opponents have spent millions dueling in the public and legislative spheres. The labor-backed groups have managed to stop Wal-Mart from opening stores in a number of communities and won isolated victories in court to force the company to increase benefit expenditures. Yet they have not fundamentally altered Wal-Mart’s behavior: Its wages are unchanged, its benefits are still restrictive, and its workers are still non-unionized. All of which raises an important question: Can progressives really change Wal-Mart–or any other company, for that matter? And if they can, at what cost?

A generation of activists has been raised on the idea of corporate social responsibility...