One of FOIA’s strongest exemptions is, unsurprisingly, for classified information. As transparency litigants are repeatedly reminded, the government is only required to provide a “logical” or “plausible” explanation for how the disclosure of classified information might be damaging to national security. However, when potentially sensitive information is not classified, the question becomes trickier. Because FOIA’s national security exemptions hinge on the classification of material, non-classified information that might otherwise implicate national security concerns does not have a clear home in any of FOIA’s exemptions.
For years, government agencies invoked Exemption 2, which exempts information “related solely to the internal personnel rules and practices of an agency,” to withhold potentially sensitive information on government operations. Relying on a 1981 D.C. Circuit decision that granted the exemption an exceptionally broad scope, agencies successfully utilized Exemption 2 to withhold a diverse array of information. This information included blueprints to buildings on a federal research campus and documents that confirmed mortgage insurance premiums by homeowners.
Justice Kagan shut down the government’s Exemption 2 party in Milner v. Department of Navy. Working from a textualist lens, Kagan concluded that the exemption was limited to “conditions of employment in federal agencies.” As a result, it did not apply to the Navy’s calculations of “minimum separation distances” required to prevent a chain reaction among stored explosives.
This decision placed pressure on agencies to formulate a new rationale to exempt non-classified information. Fortuitously for the government, Justice Alito—in a solo concurrence to Kagan’s Milner decision—tried to create an escape hatch by arguing that Exemption 7 (the law enforcement exemption) applies not only to investigations and prosecutions, “but also [to] proactive steps designed to . . . maintain security.” By slipping in “maintain security,” Alito provided a roadmap for dramatically opening up Exemption 7 far beyond its previous constructions and in a way very similar to Exemption 2’s prior interpretation.
Lower courts’ reception to Alito’s proposal has been mixed. The D.C. Circuit seized on Alito’s “important concurring opinion” to apply the exemption in a variety of cases, including inundation maps related to dams near the U.S.-Mexican border and a Department of Homeland Security protocol for shutting down wireless networks. Conversely, the Second Circuit has expressed deep skepticism at the use of Exemption 7 in this way. In ACLU v. Department of Defense, the Second Circuit warned that the exemption should not be used “as an alternative classification mechanism entirely lacking in executive safeguards and standards for classification.” It noted, as Kagan did in Milner, that the existence of Exemptions 1 and 3 cast a shadow on the use of other exemptions for national security reasons. Subsequent district court decisions in the Second Circuit have refined this language, reaffirming Exemption 7’s traditional test that the government must prove that the information “relates to anything that can fairly be characterized as a law enforcement proceeding,” a much more limited scope than the broad ambit of security maintenance.
Absent a surprise Supreme Court opinion, this debate will likely percolate through the rest of the judicial system for the foreseeable future. Its fate is uncertain. However, the Second Circuit’s resistance to such a broad application of the exemption, as well as subsequent lower court decisions in the Second Circuit, should give government transparency advocates hope that their views are represented in this legal battle.
 E.g., Wolf v. CIA, 473 F.3d 370, 374-75 (D.C. Cir. 2007).
 See 5 U.S.C. § 552(b)(1) (2012) (mandating that FOIA does not require disclosure of information that is “specifically authorized under criteria established by an Executive order to be kept secret in the interest of national defense or foreign policy and are in fact properly classified pursuant to such Executive order”); id. at § 552(b)(3) (mandating that FOIA does not require disclosure of information that is “specifically exempted from disclosure by statute”). The exemption for statutes is relevant in the national security context when the agency deploys statutes such as the National Security Act, 50 U.S.C. § 3024(i)(1) (2012), which enables the Director of National Intelligence to “protect intelligence sources and methods from unauthorized disclosure.” In addition, the government has taken the position that certain government entities, such as the National Security Council, are exempt from FOIA’s disclosure requirements. See Douglas Cox & Ramzi Kassem, Off the Record: The National Security Council, Drone Killings, and Historical Accountability, 31 Yale J. on Reg. 363, 365 (2014).
 5 U.S.C. § 552(b)(2) (2012).
 Crooker v. Bureau of Alcohol, Tobacco & Firearms, 670 F.2d 1051 (D.C. Cir. 1981).
 Elliott v. U.S. Dep’t of Agric., 596 F.3d 843 (D.C. Cir. 2010).
 Kensington Res. & Recovery v. U.S. Dep’t Hous. & Urban Dev., 620 F. Supp. 2d 908 (N.D. Ill. 2009).
 562 U.S. 562 (2011).
 Id. at 570.
 Id. at 582 (Alito, J., concurring) (citing 5 U.S.C. § 552(b)(7) (2012)).
 To be sure, Alito’s argument was not entirely novel. A smattering of lower courts had flirted with similar broad interpretation of Exemption 7. See, e.g., Living Rivers v. U.S. Bureau of Reclamation, 272 F. Supp. 2d 1313 (D. Utah 2003). However, this view did not reach prominence until Alito’s concurrence. See Michael J. Sherman, FOIA in the Aftermath of 9/11, 19 St. Thomas L. Rev. 281, 291 (2006) (noting that Exemption 7’s protections for law enforcement information that might endanger individuals has “not played a major role in post-9/11 FOIA case law”).
 Pub. Emps. for Envtl. Responsibility v. Int’l Boundary and Water Comm’n, 740 F.3d 195, 199 (D.C. Cir. 2014).
 Id. at 206.
 Elec. Privacy Info. Center v. U.S. Dep’t of Homeland Sec., 777 F.3d 518 (D.C. Cir. 2015).
 543 F.3d 59, 73 (2d Cir. 2008), vacated on other grounds, 558 U.S. 1042 (2009).
 Schwartz v. U.S. Dep’t of Def., 15-CV-7077, slip op at 28 (quoting Jefferson v. U.S. Dep’t of Justice, 28 F.3d 172, 177 (D.C. Cir. 2002)).