The Russian tank columns rumbling into Georgia reveal the anger of a tiger finally swatting the mouse that has teased it for years. South Ossetia may seem as distant, trivial and complicated as the 19th-century Schleswig-Holstein question but Russia’s fury is about much more than the Ossetians. The Caucasus matters greatly to the Russians for all sorts of reasons, none greater than the fact that it now also matters to us. The troubles in Georgia are not the equivalent of an assassinated archduke in Sarajevo. But historians may well point to this little war, beside the spectacular Olympic launch of resurgent China, as the start of the twilight of America’s sole world hegemony. If the new Great Game is for the oil of the Caucasus and Central Asia, the West may be in the process of losing it.