WARSAW, July 17: President Aleksander Kwasniewski signed the country's first post-communist Constitution yesterday, doing away with the last remnants of the communist system and preparing Poland to join the European Union and NATO.``This is the end of the eight-year-long period of provisional laws,'' he said after a live broadcast of the ceremony on television. ``New regulations create a modern state, guaranteeing all basic rights and freedoms,'' he added.The new Constitution replaces the communist-era law that was enacted in 1952. It commits the country to a democratic system based on the rule of law, guarantees personal freedom and private ownership.