China needs to control the overwhelming share of some resource or product, there needs to be no good substitutes available and China needs to be able to inflict real pain without hurting itself too badly. When China restricted rare earth exports, it woke everyone up, and companies and governments started scrambling for alternative sources. The lesson, Brooks and Vagle argue, isn’t to panic. That’s real strength, and it isn’t going away soon. Is China a titan or a house of cards?