DESPITE domestic political pressures to toughen the United States' position on China, President Bill Clinton goes into tomorrow's historic talks with his Chinese counterpart, Jiang Zemin, knowing he cannot afford to sacrifice good relations with Beijing. At issue are more than bilateral relations and access to each other's markets. America's global interests make it heavily reliant on Chinese goodwill in projecting an effective security umbrella over Asia and in the conduct of trade and diplomacy worldwide. Mr Jiang similarly knows the value of China's ties with the United States. Although the US may be less important diplomatically to China than China is to the US (because China does not have the burden of such an active global role) the closing of the American market or the loss of American technology would deal a heavy blow to China's economy and development. The reforms set out at the Communist Party Central Committee plenum would be set back, if not wrecked. Both leaders know the risks. Yet neither can afford to ignore political realities. Mr Clinton, when he is arguing his case at home, can claim confidently - as his predecessor, George Bush, did in Hong Kong this week - that economic expansion will lead togreater freedom in China. He can repeat Mr Bush's argument that a growing middle-class and its demand for pluralism will push China to more individual freedom. But he cannot pretend a new era of liberty and democracy will come about overnight. Neither his domestic critics, nor the grim reality of Chinese political suppression, will allow Mr Clinton to abandon his human rights dialogue with Beijing. He is entitled to push his views on human rights, to try to persuade China that the so-called Asian view of human rights as a reflection of national development and culture is wrong - that rights are universal and not restricted by a country's lesser state of development. And he should try to make China keenly aware that many of the countries with which it has to trade and deal diplomatically will continue to condemn its performance. But Mr Jiang did not go to Seattle just to be lectured. However much Mr Clinton would like to listen to his Democratic critics and the demands of human rights groups, he will have to live with the limitations of his power to force China to heel. It is better to use continued relations as a lever to win what concessions he can than to force Beijing into a corner where its only response will be defiance and self-imposed isolation.