SinceGeorgeW.Bushassumedthepresidencyinearly2001,atensesituationhadoccurredintherelationshipsamongworldbigpowers.IntheaftermathofSeptember11,significantimprovementhasbeenmadeinSino-U.S.andRussia-U.S.relations.Inthemeantime,correspondingchangeshavetakenplaceinEU-U.S.andRussia-Chinarelations.