President Clinton will close years of political and economic debate Tuesday and seal a major achievement of his administration by signing off on normalized trade with China.Clinton will sign the measure, approved by Congress this year, in a White House ceremony Tuesday afternoon. The president has invited key lawmakers to the South Lawn to witness his signing of the U.S.-China Relations Act of 2000.The bill's passage by the Senate on September 19 capped years of negotiations with Beijing and intense lobbying by the Clinton administration, business and labor interests. The move is designed to open China's mammoth market to U.S. businesses and pave the way for China's entry into the World Trade Organization, ending a 20-year-old U.S. ritual of annually reviewing China's trade status.The bill survived a bruising battle in the House of Representatives in May, and Clinton has hailed the measure as a turning point in relations between the world's richest and most populous nations.Granting permanent, normal trade relations to China is considered the most important U.S. trade legislation since passage of the North American Free Trade Agreement in 1993. But it faced a long campaign of opposition from labor, human rights and conservative groups who wanted to retain the annual review of trade relations with China.