JAMES BAKER III, US secretary of state, travels to Beijing today as part of his Asian tour. Some in the US view the occasion as a dramatic event - the highest US official to visit China since Tiananmen Square.Since other nations, Japan particularly, are starting to normalize relations with China, Mr. Baker's trip has been cast as the last chance for the US to make Chinese officials understand they will pay for their ongoing human rights abuses. Certainly Baker must take a tough stand on human rights, both in public statements while in China and in private conversation with the country's leaders. But the overall purpose of his trip is to take care of business with a major world player. Three heads of state have been to Beijing before him - Mr. Androtti of Italy, Mr. Kaifu of Japan, and Mr. Major of Britain. Some ice has already been broken and some human rights messages received. Had Mr. Bush made the trip (he toyed with the idea) expectations would be different. Baker is visiting as a foreign minister with a world agenda that includes the Chinese. The Chinese have isolated themselves through their actions, but Baker must keep in touch. The Chinese helped deliver a temporary peace in Cambodia. They are backing off sending M-11 missiles to Pakistan. They are a crucial player in any dealings with North Korea, a nation with a growing capacity for nuclear technology. The secretary of state will inform Chinese officials of US regional and global interests and plans. Baker should also candidly convey the domestic political context of his trip. The White House has taken heat from Congress for its relatively lenient policy toward China. But the Chinese have made few concessions from the White House point of view. For example: Where is the promised signature on the nuclear non-proliferation pact, something Beijing got headlines for last spring? What is holding up the easing of Chinese trade restrictions on US products and other fair business practices? How aware is Beijing that further evidence of the use of slave labor to manufacture goods for export will endanger most-favored-nation trade status? Does China realize that Congress is "increasingly responsive to the idea of doing business with Taiwan," as James Cla d of the Carnegie Endowment notes? Baker's trip is not the last chance for the US to make itself heard on human rights. Contact will continue; so should protests. Adjustments in China's domestic and foreign policies should come as Beijing's leadership crisis is solved. Meanwhile, the US has to tend to its interests in Asia.