both china and russia fear the united states (especially following its strengthened geopolitical position following the september 11, 2001 attacks) becoming involved in areas which they believe should only be affected by their respective spheres of national influences and interests: for china, this largely involves taiwan serving as a us client state, while for russia it involves having various former soviet republics as us client states. many of these do not border either country, though kyrgyzstan and tajikistan border china, and kazakhstan borders both.