▁if ▁W ał ę sa ▁could ▁be ▁elected ▁as ▁President ▁only ▁eleven ▁months ▁after . ▁The ▁Wars aw ▁P act ▁was ▁soon ▁followed ▁on ▁ 1 ▁July ▁ 1 9 9 1 ▁and ▁the ▁Soviet ▁Union ▁ceased ▁to ▁exist ▁in ▁December ▁ 1 9 9 1 . ▁On ▁ 2 7 ▁October ▁ 1 9 9 1 , ▁the ▁first ▁entirely ▁free ▁Polish ▁parliament ary ▁elections ▁since ▁the ▁ 1 9 2 0 s ▁took ▁place . ▁This ▁completed ▁Poland ' s ▁transition ▁from ▁a ▁commun ist ▁party ▁rule ▁to ▁a ▁Western - style ▁liberal ▁dem ocr atic ▁political ▁system . ▁The ▁last ▁post - S ov iet ▁troops ▁left ▁Poland ▁on ▁ 1 8 ▁September ▁ 1 9 9 3 . ▁After ▁ten ▁years ▁of ▁dem ocr atic ▁cons olid ation , ▁Poland ▁joined ▁O E CD ▁in ▁ 1 9 9 6 , ▁NAT O ▁in ▁ 1 9 9 9 ▁and ▁the ▁European ▁Union ▁in ▁ 2 0 0 4 . ▁ ▁Government ▁and ▁politics ▁▁ ▁The ▁government ▁and ▁politics ▁of ▁the ▁Polish ▁People ' s ▁Republic ▁were ▁govern ed ▁by ▁the ▁Polish ▁United ▁Work ers ' ▁Party ▁( Pol ska ▁Z jed noc z ona ▁Part ia ▁Rob ot nic za , ▁P Z PR ). ▁Despite ▁the ▁presence ▁of ▁two ▁minor ▁parties , ▁the ▁United ▁People ' s ▁Party ▁and ▁the ▁Democratic ▁Party , ▁the ▁country ▁was ▁generally ▁reck oned ▁by ▁western ▁nations ▁as ▁a ▁one - party ▁state ▁because ▁these ▁two ▁parties ▁were ▁supposed ly ▁completely ▁sub