Washington has established buffer states in Eastern Europe between Russia and Germany. The United States opposes cooperation between Russia and Germany, fearing the strength of such an alliance.
There are no "buffer states" between Germany and Russia; the USA did not "establish" buffer states in Eastern Europe. Recurring pro-Kremlin disinformation narrative about German-American relations and Western dominance in Europe.
The successor 15 states of the USSR, which emerged after the collapse of the USSR are independent countries, whose sovereignty is recognized by the international community.