On Monday evening, William S. Castle, the Pentagon’s top lawyer, gave a speech entitled, “Congressional Authorizations on Use of Force?,” at the New York City Bar Association. Mr. Castle is the Defense Department’s Principal Deputy General Counsel performing the duties of the General Counsel. The organizers of the event titled the panel, “The Global War on Terrorism: Do We Need a New AUMF?”
Mr. Castle’s speech outlined the Trump administration’s position in two main areas: (1) the statutory basis for use of military force against al-Qa’ida, the Taliban, and ISIS under the 2001 and 2002 congressional authorizations for use of military force (AUMFs); and (2) the design of any future legislative efforts to explicitly approve force against ISIS or to repeal the existing 2001 and 2002 authorities.
The first part of Mr. Castle’s speech is highly consistent with similar speeches given by senior national security lawyers over the past several years. Mr. Castle, for example, described a two-part test for determining which “associated forces” of al-Qa’ida and the Taliban are covered by the 2001 AUMF. His test is word-for-word the same elements outlined in a 2012 speech by then-General Counsel of the Pentagon Jeh Johnsen. Mr. Castle’s explanation for how ISIS comes under the 2001 and 2002 AUMFs also closely tracks a 2015 speech by then-General Counsel of the DoD Stephen Preston. One line that may appear remarkable in Mr. Castle’s remarks is that “ISIS has engaged in terrorist attacks against the United States throughout its existence.” But that too is not far different from Mr. Preston’s stating, “we would be having a different conversation if ISIL had emerged out of nowhere a year ago … or if the group once known as AQI had, for example, renounced terrorist violence against the United States at some point along the way. But … the group certainly has never laid down its arms in its conflict against the United States. The name may have changed, but the group we call ISIL today has been an enemy of the United States within the scope of the 2001 AUMF continuously since at least 2004.” (As an aside: in 2014, I wrote a two–part essay raising concerns about interpreting the 2001 AUMF to cover ISIS.)
The second part of Mr. Castle’s speech highlight concerns that Congress would impose restrictions—including temporal or geographic limits—on any new AUMF against ISIS. There is some daylight here between the Trump and Obama administrations. In December 2014, then-Secretary of State John Kerry told Congress that his administration would accept a sunset clause in an ISIS AUMF. Mr. Castle also expressed concerns about repealing either the 2001 or 2002 AUMF as part of that legislative effort. “The prospect of unintended consequences,” Mr. Castle stated, “frankly keep me up at night,” especially since the issues in this space involve momentous decisions implicating the use of military force. The Obama administration did propose repealing the 2002 Iraq AUMF, including as part of a draft ISIS AUMF that it submitted to the Hill. Finally, Mr. Castle ended in describing the positive role that a new AUMF could play as “a statement of continued Congressional support for these operations” and a show of “national unity.”
The full text of Mr. Castle’s speech follows:
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