British Prime Minister Theresa May made the remarkable statement Monday that, absent a credible response from the Russian government, the United Kingdom will conclude that the use of a nerve agent against a former Russian informant, Sergei Skripal, was “an unlawful use of force by the Russian state against the United Kingdom.” News reports have proliferated, but some of them are inaccurate or incomplete. There are two recurring issues that warrant clarification: the possible role of the North Atlanic Treaty Organization in a U.K. response, and the range of possible U.K. actions.

Ashley S. Deeks, Prime Minister May’s Use of Force Claim: Clarifying the Law That Governs the U.K.’s Options, Lawfare (March 13, 2018).