In response to NATO, Eastern European nations including Poland & the USSR signed this 1955 treaty
was a collective defense treaty 
among the Soviet Union and seven other Soviet satellite states in Central and 
Eastern Europe .... On 14 May 1955, the USSR and other seven European 
countries "reaffirming... [DOC] [TLE] The Warsaw Pact [PAR] Unlike NATO, founded in 1949, however, the Warsaw Pact does not have an .... 
On May 14, 1955, the Soviet Union and its East European allies signed the 
Warsaw Pact.