It turns out that organized labor’s battle against Wal-Mart is more than a war on the lower-income Americans who depend on the big-box store’s “always low prices.” The unions are also after the First Amendment. Wal-Mart Watch, an opposition group supported by unions, has sent letters to the attorneys general of Arizona and Nebraska asking them to outlaw television spots Wal-Mart is running in those states. Wal-Mart Watch claims the states can do this thanks to consumer-protection laws that require truth in advertising.

Those laws are targeted at companies’ claims about the weight of a Quarter Pounder or the ingredients of a bar of soap, however, and what’s at issue in respect of the Wal-Mart ads is something else. Wal-Mart is attempting to counter the attacks of its critics by presenting its case directly to the public. Wal-Mart Watch complains that the TV spots say “Wal-Mart saves the average working family $2300 per year.” Wal-Mart Watch claims this is deceptive because that number comes from a Wal-Mart funded study performed by a firm called Global Insight. “This ‘fact’ has been discredited,” Wal-Mart Watch writes to the attorneys general, “by a leading economic research think tank, the Economic Policy Institute.”

It can easily be argued, however, that EPI isn’t “objective” either. Nine of its 19 board members, after all, are leaders of labor unions. One of those just happens to be Andrew Stern, president of the Service Employees International Union, which has been a supporter of anti-Wal-Mart efforts. Mr. Stern also serves on another board — that of Wal-Mart Watch, which he chairs. The unions and EPI certainly are entitled to their own analysis of Wal-Mart’s economic impacts, but with their latest move they are trying to enlist state attorneys general to substitute the unions’ views for, well, public debate.

They are trying to do so by taking advantage of a gray area in First Amendment law. Courts have ruled that states can regulate commercial speech like advertising to guarantee its accuracy, but it is still unclear how far into the political realm that power extends. The Supreme Court punted on the issue in 2002, ultimately declining to pass judgment on a case involving Nike, and another Wal-Mart case is working its way through the federal courts in California.

The danger here is that a judge or an attorney general (or two) might be tempted to substitute his judgment for that of individual members of the public. In the marketplace of ideas, Wal-Mart has as much right to present its side of the story to the public as the unions do, and people can take or leave any “fact” they want. It would be a perversion of commercial speech laws, let alone the First Amendment, to abridge Wal-Mart’s rights just because some unions don’t like what the company is saying.