THROUGHOUT our history, Americans have prided themselves on the power of the democratic ideal. We have the conviction that, over time, no government can resist democracy once its people have tasted the sweetness of freedom. In my view, it is time to test this belief in Vietnam.Sixteen years ago, the United States imposed a trade embargo on Hanoi. Last month at the Yale commencement exercises, President Bush gave an eloquent explanation of why it should end. He was defending trade with China, but the logic applies equally to Vietnam: "It comes down to the strength of our belief in the power of the democratic idea. If we pursue a policy that cultivates contacts ... promotes commerce to our benefit, we can help create a climate for democratic change.... No nation on earth has discovered a way to import the world's goods and services while stopping foreign ideas at the border." I, too, believe that we should display the fruits of freedom at every opportunity. So I authored legislation, recently adopted by the Senate Foreign Relations Committee, that urges increased access into Vietnam and a lifting of our outdated trade embargo with regard to nonstrategic goods and services. This action, though not a resumption of any formal relations, represents a crucial step toward ending the Vietnam war. We must, of course, maintain pressure on Hanoi over the POW/MIA issue. But exchanges between our two countries and the presence of Americans in Vietnam are far more likely than isolation to resolve this crucial issue. Traditionally, we have built bridges to old adversaries. American magnanimity toward former enemies nurtured the development of democracy in Germany and Japan. Exposure to Western economics and ideas laid the foundation for the rebirth of democracy in Eastern Europe. The same tools can work in Vietnam. But US policymakers seem unable to shake their old habits. Two months ago, the administration laid out a new set of conditions for restoring relations with Hanoi, known as the "road map." Officials who presented the road map to Congress acknowledged it would take another "year or two" for the conditions to be met. Meanwhile, Americans are losing competitive ground to investors from Germany, Japan, Britain, France, and Hong Kong. These countries have initiated more than $1.4 billion in projects with Vietnam since Hanoi opened to foreign business. The biggest victims of the US trade embargo are Americans themselves. Nearly 70 percent of Vietnam's offshore oil tracts, many of which Vietnam initially held in reserve for American oil companies, already have been taken. The other 30 percent will likely be opened to bidding this summer. Important financial, construction, telecommunications, and consumer markets are also being lost because US firms are banned from the competition. Yet the goal of US policy keeps shifting whenever Vietnam appears to meet our terms for resuming economic relations. At one time, US policy said Hanoi had to withdraw its troops from Cambodia and fully cooperate with efforts to determine the fate of POW/MIAs from the Vietnam conflict. Vietnam's troops are long gone from Cambodia and there has been progress on the POW/MIA issue. But the "road map" now includes a new condition - it requires a Cambodian peace settlement which Vietnam is powerless to deliver. After 16 years of isolation, it is time for a new approach to Vietnam. We need full and open access to Vietnam, so that we can bring the light of day to unresolved POW/MIA cases. And a satisfactory resolution of the Vietnam issue would permit US companies to compete in this growing market, and advance democracy by introducing Western ideas. At Yale, President Bush warned against "righteous isolationism," declaring that "we will not be able to advance our cause or resist repression if we pull back." His words ring true, and they apply to Vietnam as well.