Following EFF’s victory in a four-year Freedom of Information Act lawsuit, the government released an opinion (pdf), written by the Office of Legal Counsel (OLC) in 2010, that concluded that Section 215—the provision of the Patriot Act the NSA relies on to collect millions of Americans’ phone records—does have a limit: census data.

The Commerce Department requested an OLC opinion on whether any provisions of the Patriot Act could override the privacy requirements of the Census Act, provisions which, as the opinion acknowledges, “have long provided assurances of confidentiality to” census participants. The opinion contrasts the “broad authority” and “substantial new powers” provided by Section 215 with the “long history of congressional enactments providing broad confidentiality protection to census information.” Ultimately, OLC concluded that “section 215 should not be construed to repeal otherwise applicable Census Act protections for covered census information” and that the “Patriot Act, as amended, does not alter the confidentiality” of census data.

That, however, was not the view of Department of Justice’s National Security Division (NSD). As the opinion notes, the National Security Division “disagreed, contending that section 215 . . . may allow for a court order to compel the Secretary [of Commerce] to disclose furnished census information.” Importantly, the National Security Division is the division of DOJ that represents the government in cases before the Foreign Intelligence Surveillance Court (FISC), the secret court that oversees much of the government’s domestic spying operations. Thanks to disclosures in EFF’s lawsuit, we know that NSD ultimately cited and relied on this opinion in proceedings before the FISC. That application, however, remains secret.

Fortunately, and as EFF has long argued, the opinions of the OLC are the law of the executive branch. So, even if attorneys in the National Security Division disagreed with OLC’s conclusions, they were obligated to follow it. The judge in EFF’s FOIA case, who reviewed the government’s application to the FISC that relied on the opinion, acknowledged as much in her opinion (pdf): “The Court’s in camera review confirms that DOJ cited the Census Memorandum in an application to the FISC, referencing it as DOJ’s legal position on the census-related issues therein, and contrasting it with other legal issues argued in the application. DOJ offered the Census Memorandum as a statement of the law to bolster its legal arguments concerning matters unrelated to the subject of the Census Memorandum itself.”

The federal government has a sad history of using census data to target politically vulnerable groups, but we’re pleased that the executive branch, in this opinion, has recognized the important privacy protections Congress has established for census data. We’re also pleased that the government, for once, has acknowledged Section 215 has its limits. But it shouldn’t have taken a four-year court battle for the public to know what the government thinks the law is. We’ll keep fighting against secret surveillance law and for the public’s right to know.