Every time you fill a prescription at a drug store like Walgreens, the pharmacy keeps a record of the transaction, noting information such as your name, the drug, the dosage, and the issuing doctor. It’s a routine bit of bookkeeping, and for a long time it raised few eyebrows. Then a firm called IMS Health starting buying up the data. Mining pharmacy records, the company assembled profiles of hundreds of thousands of American doctors and millions of individual patients, with names and other identifying details encrypted. IMS Health turned around and sold access to those files to pharmaceutical companies, making it easier for the firms to target (and reward) the physicians most likely to prescribe expensive, brand-name drugs.

Eventually, doctors and state officials caught on to what IMS Health was doing. Where the company saw a business opportunity, they saw a strategy that violated patient privacy and could increase health care costs. Three states—New Hampshire, Maine, and Vermont—decided in 2006 and 2007 to ban pharmacies from selling prescription records for commercial purposes. By late 2010, 26 other states were considering similar measures.

Had the issue remained subject to a normal democratic process, it would have continued to play out that way—through a gradual, state-by-state debate about whether so-called “prescription confidentiality” laws make for good policy. But IMS Health did not want that kind of fight. Instead, it filed separate suits against the three states that had first cracked down on its business, invoking the First Amendment. The selling of prescription records, the company asserted, is a form of free speech.

For most of U.S. history, such a claim would have been a dead letter in court. But when it comes to the First Amendment, we live in interesting times. In June 2011, the Supreme Court struck down the new data-protection laws, arguing that they discriminated against IMS Health. “The State,” wrote Justice Anthony Kennedy for the majority, “has burdened a form of protected expression. ... This the State cannot do.”

It was Kennedy, of course, who authored Citizens United, which established that independent political spending by corporations is shielded by the Bill of Rights as well. The IMS Health case, which drew much less attention, shows just how pervasive such free speech arguments have become. Once the patron saint of protesters and the disenfranchised, the First Amendment has become the darling of economic libertarians and corporate lawyers who have recognized its power to immunize private enterprise from legal restraint. It is tempting to call it the new nuclear option for undermining regulation, except that its deployment is shockingly routine.