Science & Technology

The defining question about global order for this generation is whether China and the United States can escape Thucydides’s Trap. The Greek historian’s metaphor reminds us of the attendant dangers when a rising power rivals a ruling power—as Athens challenged Sparta in ancient Greece, or as Germany did Britain a century ago. Most such contests have ended badly, often for both nations, a team of mine at the Harvard Belfer Center for Science and International Affairs has concluded after analyzing the historical record. In 12 of 16 cases over the past 500 years, the result was war. When the parties avoided war, it required huge, painful adjustments in attitudes and actions on the part not just of the challenger but also the challenged.

"While Obama was hardly the first American politician to use the Internet, he was the most effective in using new technology to raise money from small donors, energize and coordinate volunteers, and convey his messages directly to voters. Now he is faced with the question of how to use networks to govern....In a networked world, leadership is more like being in the middle of the circle and attracting others than being "king of the mountain" and issuing orders to subordinates down below."