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Beijing has fervently denounced U.S. President Barack Obama's plan to sell more arms to Taiwan, and loudly demanded that he break his coming date with the Dalai Lama. Is this proof that China-U.S. relations have entered a radically new and deeply worrisome phase?

It's tempting to see it that way. There has been much talk of China ruling the world and the clash of civilizations this would prompt. Much has been made of the notion that Chinese leaders have been showing an unexpected cockiness vis-à-vis the U.S. of late, tightly controlling what Obama did when in China, refusing to follow American leads in Copenhagen and then lambasting Secretary of State Hillary Clinton for criticizing Beijing in a Jan. 21 speech on Internet freedom. But it's a temptation worth...