If proof were needed of the significance of the crisis facing the troubled Caucasus state of Georgia, it came on Tueday with the start of exercises involving 1,000 US troops.

US officials insist the long-planned wargames have nothing to do with the recent dispute between Russia and Georgia over the breakaway Georgian regions of Abkhazia and South Ossetia. But they give Washington a chance to support pro-west Tbilisi at a critical time.