Newly declassified documents shed light on a disagreement within the Department of Justice over whether or not spies can tap into protected Census Bureau data.

According to a 2010 DOJ Office of Legal Counsel memo made public for the first time on Thursday, department lawyers concluded that broad spying powers created by section 215 of the USA PATRIOT Act do not trump privacy protections outlined in the Census Act.

That legal opinion was released after a several year-long battle between the government and the Electronic Frontier Foundation, which had filed a Freedom of Information Act request for the documents, as The Sentinel previously reported.

Both the FBI and the department’s Civil Rights Division agreed that census data was off-limits. But the documents show that the DOJ’s National Security Division (NSD), which handles the government’s spying requests in front of the top-secret Foreign Intelligence Surveillance Court (FISC), believed that privileged census data held by the Secretary of Commerce was ripe for the taking.

“The National Security Division disagreed, contending that section 215 of the Patriot Act, as amended, may allow for a court order to compel the Secretary to disclose furnished census information,” the OLC memo reads.

The dissenting opinion from the National Security Division is notable given the latitude the body has in arguing cases before the Foreign Intelligence Surveillance Court, which despite its name, often approves of domestic surveillance initiatives as well.

The court lacks any sort of adversary protecting privacy rights against government requests for surveillance. As a result, the court approves 99 percent of requests brought by the NSD.

The OLC memo shows that NSD’s view of the government’s surveillance authority, at times, extends beyond the confines of the law.

According to section 215, the FBI has authority to obtain ‘’tangible things,” like documents, books, or, as revealed by former NSA contractor Edward Snowden, call records belonging to millions of Americans, for use in certain terrorism investigation.

“Strictly speaking, the plain text of section 215 could be read-to conflict with the confidentiality provision of the Census Act, as the phrase ‘any tangible things’ could be construed to encompass census records,” states the OLC. “Nonetheless, we think section 215 is better read not to have this significant consequence.” The legal team referenced “prior executive branch precedent” that supports the conclusion.

The OLC memo represents official legal policy for the department.

One lingering question is why the government fought so hard to keep the memo secret, especially since it appears to restrict government spying – a message that could offer beneficial PR to spy agencies.

Investigative journalist Marcy Wheeler posits that the opinion could endanger rulings made by the FISC stating that section 215 preempts other privacy statues. Also, she said, the stated position of the NSD in the memo that the government should have access to census data might mean that authorities have been fishing for that data from other non-governmental sources like private marketing brokers.

Aside from the tough legal battle, the Electronic Frontier Foundation was largely “pleased” with the OLC’s legal opinion.

“The government, for once, has acknowledged Section 215 has its limits,” wrote EFF staff attorney Mark Rumold in a statement.