BEIJING — The White House dispatched 200 dignitaries to China’s capital for relationship-cementing talks this week, a number that bespeaks a world order rapidly turning upside down. From China’s threefold economic growth in a decade to today’s swarms of five-star hotels and six-figure autos, it is a cliché to say that the world has never before seen anything like this juggernaut. Actually, the world has. Twenty years ago, Japan was the juggernaut, a silky economic machine poised, according to conventional wisdom and more than a few best sellers, to dominate world trade and global diplomacy in…