So President Obama is to visit China. Its blistering economic growth, reserves of $ 1 trillion and enormous armed forces has made China a dangerous and arrogant bully. On climate China will put the onus totally on the US and the west. On North Korea, Burma and Iran China will obfuscate with talk about sovereignty. On human rights violations its denial will be brusque. However on trade Chinese smiles will be crocodilian. They will strongly agree on free trade, oppose any increase in tariffs and deride non tariff barriers. When pushed on the enormous imbalance in the balance of payments in favour of the Chinese they virtuously point out how they have stimulated internal demand by injections of large amounts of cash and will flatly refuse to float the yuan so that it can appreciate against the dollar and keeeping it fixed at around 8 to a dollar. This will be the point when Mr. Obama can use his sucker punch. He can politely remind the Chinese that just as the Chinese claim the right to set the exchange rate of the yuan the americans do the same with the dollar and henceforth the dollar will buy, say, six yuans for Chinese imports making them instantly expensive. The Chinese will howl but they will be hoist by their own arguments. Unfortunately Mr. Obama will not dare because US businesses will not let him so like his predecessors he will return with his tail between his legs.