Today's visit to Hanoi by US Secretary of Defence William Cohen has more than symbolic importance. It is part of a broader US effort to improve relations with Vietnam - a country, not a war, as its officials like to say - and pull it more firmly into the world community. If successful, the effort could benefit Hong Kong and the region. Vietnam, a poor nation of 80 million people, sits mostly apart from global trade flows and suffers for it. Getting the country involved would help its flagging economy and the whole region's economic revival. Mr Cohen, who has just called here on SAR officials and a three-month-old grandson, will be the first Pentagon chief to visit since the fall of Saigon in 1975. He does not expect major breakthroughs from his Hanoi meetings with defence officials and Prime Minister Phan Van Khai, but does have a specific agenda designed to move relations forward. For domestic reasons, Mr Cohen must first seek continued help in the search for the remains of American servicemen lost in the war. Beyond that, however, he plans 'to send a signal' that the US wants stronger military links with its former enemy in the context of better overall relations. He will propose, for example, joint military operations in civil engineering, flood control, disease control and de-mining. Whether he will succeed is impossible to predict. Washington and Hanoi have already negotiated a trade treaty, which Vietnam then shelved. Its Communist Party rulers are afraid to implement it for fear economic reforms might weaken their political control; they are not ready to match the risk-taking of their Chinese counterparts. As the World Bank and others have noted, Vietnam needs help. Mr Cohen's mission may encourage Hanoi to be less fearful of the changing world around it.