It has become conventional wisdom that America and China are running a "superpower marathon." Yet Hal Brands and Michael Beckley pose a counterintuitive question: What if the sharpest phase of that competition is more like a decade-long sprint?The Sino-American contest is driven by clashing geopolitical interests and a stark ideological dispute over whether authoritarianism or democracy will dominate the twenty-first century. But both history and China's current trajectory suggest that this rivalry will reach its moment of maximum danger in the 2020s.China is at a perilous moment: strong enough to violently challenge the existing order, yet losing confidence that time is on its side. Witness its aggression toward Taiwan, its record-breaking military buildup, and its efforts to dominate the critical technologies that will shape the world's future.The Chinese challenge will most likely prove more manageable than many pessimists currently believe-but during the 2020s, the pace of Sino-American conflict will accelerate, and the prospect of war will be frighteningly real. America, Brands and Beckley argue, will still need a sustainable approach to winning a protracted global competition.