We have witnessed a number of significant challenges to international security in recent years. Some crises have arisen so quickly and with so little warning that national security professionals have had difficulty responding in ways that maintain strategic balance. Other challenges have emerged so slowly and over such a vast scale that near-term options appear limited. How to determine in real time what is a tectonic shift and what is merely a low-magnitude tremor? How to anticipate events and set clear policy goals at a time of such dynamism?