The U.S. Assistant Secretary of State for East Asia issued a stern warning to Beijing yesterday: Don’t even think about using force to annex islands in the South China Sea, as Russia did in Crimea.“The prospect of the kind of incremental retaliatory steps that are gradually being imposed on Russia in terms of its banks, in terms of cronies and other areas should have a chilling effect on anyone in China who might contemplate the Crimea annexation as a model,” Daniel Russel said. “The net effect is to put more pressure on China to demonstrate that it remains committed to the peaceful resolution of the problems.”“The president of the United States and the Obama administration is firmly committed to honoring our defense commitments to our allies,” he continued.China has been paying attention to the West’s response Russia, which has so far included nothing more than anemic sanctions and the categorical ruling-out of the military option. And sanctioning China is riskier for the U.S. than sanctioning Russia is, as Gideon Rachman writes in the Financial Times: “In theory, the U.S. could restrict the imports of Chinese goods – or even, in extremis, use the US navy to block China’s energy imports. But, like the Russians, the Chinese would have plenty of economic weapons with which to retaliate, from the disruption of the supply chains of American corporations to a refusal to buy U.S. Treasury bills.”On his upcoming trip to Asia, President Obama is expected to reassure America’s allies in Asia that the U.S. will support them, and with deeds as well as words. As they grow increasingly nervous about China, the President will have his work cut out for him.