During her first few months in office, German Chancellor Angela Merkel has attained the kind of approval rating that politicians the world over dream about, largely due to the way she has handled herself on international matters in visits to Washington, Moscow and Brussels. According to a poll by Der Spiegel , the newsweekly, 85% of Germans like the way Merkel is doing her job. But ask any politician — George Bush, Tony Blair, Jacques Chirac — about the likelihood of retaining such a lofty number and they’ll tell you that what goes up can just as readily come down, especially when tough domestic issues have to be addressed. In Merkel’s case, that means trying to figure out ways to juice up Germany’s economy, Europe’s largest and the world’s third biggest.…