Whichever party or parties form the next UK government, a Strategic Defence and Security Review (SDSR) is expected to begin soon after the general election in May. The review might be a ‘light touch’ exercise—little more than a reaffirmation of the SDSR produced by the coalition government in 2010. It seems more likely, however, that the review will be a lengthier, more deliberate exercise and one which might even last into 2016. For those most closely engaged in the process the challenge is more complex than that confronted by their predecessors in 2010. The international security context is more confused and contradictory; the UK’s financial predicament is still grave; security threats and challenges will emerge that cannot be ignored; the population’s appetite for foreign military engagement appears nevertheless to be restricted; and prevailing conditions suggest that the risk-based approach to national strategy might be proving difficult to sustain. Two key questions should be asked of the review. First, in the light of recent military experiences, what is the purpose of the United Kingdom’s armed forces? Second, will SDSR 2015–16 sustain the risk-based approach to national strategy set out in 2010, and if so how convincingly? Beginning with a review of the background against which SDSR 2015–16 will be prepared, this article examines both enduring and immediate challenges to the national strategic process in the United Kingdom and concludes by arguing for strategic latency as a conceptual device which can complement, if not reinvigorate, the risk-based approach to national strategy and defence.