AFTER years of isolation, Communist-run Vietnam is coming in from the cold, and fast.
Last week, it won official recognition from the United States after 20 years of chilly postwar relations. Yesterday, Vietnam and the European Union signed a pact on aid and cooperation. And Russia's foreign minister is due here in a week to rejuvenate old Hanoi-Moscow ties that languished after the cold war.
Most of all, however, this nation of 72 million people will take a big step next week to integrate itself into Asia's fastest-growing economies. It will join a regional group whose original aim was to stop the spread of communism.
Vietnam's entry into the six-member Association of Southeast Asian Nations (ASEAN) on July 28 at a meeting in Brunei will cap a banner month for the diversified diplomacy of a country once treated as an international outcast.
ASEAN - which now includes Thailand, Malaysia, Singapore, Indonesia, Brunei, and the Philippines - will welcome Vietnam as a fellow capitalist country, even though politically Vietnam remains under the tight control of a communist party.
Formed in 1967 at the height of the Vietnam war, ASEAN is now more interested in trade and investment with Vietnam than it is in isolating it on ideological grounds. Adding another country also helps the group gain a stronger voice for its members in global forums.
Officials in Hanoi hope that ASEAN membership will change Vietnam's international image from that of a fossilized communist state with limited links to the outside world to an emerging Asian ''economic tiger.''
ASEAN ties will also allow easier travel for Vietnamese to partner nations. A Vietnamese seeking a tourist visa to Thailand, for example, now must post a guarantee of $800 to ensure he or she returns home. Once Hanoi signs consular agreements with ASEAN, its citizens will be able to travel without a visa to any member country for up to 15 days.
''To integrate into the region is the long-term and inevitable goal of Vietnam's foreign affairs,'' says Nguyen Ngoc Truong, editor in chief of World Affairs Weekly, a newspaper affiliated with the foreign ministry.
Mr. Truong says such a step was one of the most important diplomatic goals of the late communist leader Ho Chi Minh.
''It's all benefits for Vietnam,'' said former Singapore Prime Minister Lee Kuan Yew during a visit to Hanoi in March. ''There are no disadvantages.''
Vietnam badly needs technology and investment to help develop its infant market economy. By entering ASEAN, it hopes to adapt more quickly to the rigors of international competition and catch up with its fast-growing Asian neighbors.
''We cannot stand outside the international organizations to see their members surging ahead,'' Deputy Foreign Minister Vu Khoan wrote this month in an editorial in the official Vietnam News. ''We cannot let time pass [and remain] in isolation, left behind.''
ASEAN countries have already pledged investments worth $2.7 billion and account together for 30 percent of Vietnam's trade.
Vietnam must take the added step of joining the planned ASEAN Free Trade Areas, however, if it is to collect the full economic payoff of its new partnership. Member nations are planning to cut tariffs on most goods to 5 percent or less by the year 2003 to create a free-trade area.
Nguyen Quoc Dung, director of the foreign ministry's economic department, acknowledges the need to reduce tariffs but says it won't be easy for some Vietnamese industries that are still too weak to compete with foreign imports. Vietnamese leaders are asking for more time to comply.
''If you're a member of the club, you have to play by the rules,'' says the Hanoi-based ambassador for one ASEAN country.
Joining ASEAN helps Hanoi bolster its sometimes-tense ties against Beijing, its historic adversary. And both Vietnam and ASEAN hope to enhance their collective security in the face of China's aggressive moves earlier this year to expand its territorial claims in the South China Sea.
Normally reticent in dealing with Beijing, ASEAN made its first unified statement against Beijing's recent grab for islands claimed by Manila. But, says editor Truong, ''Joining ASEAN doesn't mean we choose sides.''
Still, with Cambodia, Laos, and Burma likely to follow Vietnam into ASEAN, the group has the potential to become a substantial counterweight to China, as well as a big trading bloc.