WESTMINSTER, CALIFORNIA — Westminster, California. -- "Little Saigon'' is now the name of an exit on the San Diego Freeway in Orange County, 30 miles south of Los Angeles International Airport. I came down here only a few days after seeing big Saigon, the real thing in Vietnam, which is now officially called Ho Chi Minh City. It's hard to tell the difference sometimes.
Some of the sights and the sounds and smells are the same, even though Bolsa Avenue, the main street of Westminster, is lined with neon-bright service stations, and the Saigon equivalents are squatting entrepreneurs on every street corner with little plastic bottles of gasoline and rusty bicycle pumps ready for bikes and Honda motor scooters.
Both cities are places of great pain, beginning with the separation of thousands of Vietnamese families divided between California and the old country.
The entrance to the Man Wah shopping center on Bolsa Avenue here is guarded by three Buddhas marked ''Fortune,'' ''Prosperity'' and ''Longevity'' -- all against the backdrop of a huge American flag.
There are close to 1 million Vietnamese in the United States, a number that increases at least 20,000 each year under an ''orderly departure'' program adopted in 1979 for citizens of Vietnam with relatives already in the United States. The program, one of the very few agreed to by the two governments, is like water torture or endless war -- slow and maddening -- for people on both sides.
About half the Vietnamese immigrants or refugees live in California. The other states with significant numbers of Vietnamese are Virginia, Louisiana and Texas. And more than half the Californians live within shopping distance of the Man Wah and Wai Wai and 1,500 other Vietnamese-owned businesses on or near Bolsa Avenue.
Even here, where there are three Vietnamese-language newspapers and videotapes of Ho Chi Minh City play in the endless din of music from home, there are divisions that split generations, families and personalities. Mothers and fathers and grandparents speak Vietnamese and tend to be zealous ''We Shall Return'' anti-communists; many of them were officials or military officers of the old South Vietnamese governments or employees of the Americans before we abandoned the country in 1975. Some are not only fanatically anti-communist, they openly threaten or even kill anyone talking of solidarity with the Vietnamese left behind or those here who yearn to visit the old country. The young speak English American-style and either care nothing about the land of their fathers or are desperately curious to see that land far away.
There is a myth that the Vietnamese in America, valedictorians all, are the smartest, the most hard-working, family-oriented, prosperous and happy of modern immigrants. Only the part about family is the whole truth; two-thirds of Vietnamese-Americans are poor by any standard. Many still consider themselves ''refugees'' rather than ''immigrants,'' asserting that they will go home when the communists are gone. They are as divided as Cubans in Miami 25 years ago. And, like the Cubans, and before them Jews from Germany or Russia, the early arrivals have done much better and tend to look down on their late-coming brethren.
There are 1975 Vietnamese, including the former Premier Nguyen Cao Ky, who lives in Westminster, and then there are the ''boat people,'' the ones who came in the 1980s. The first group was urban and educated. Three-quarters of the first arrivals spoke some English and usually French, too; half were college graduates and half were Christians. The ''boat people'' who came later were poor at home, peasants and ordinary soldiers who usually spent years in prison or refugee camps, and they are poor here, a majority on welfare in many places.
The contrasts in the Vietnamese-American experience show at Westminster High School, where 30 percent of the students are Vietnamese. More than half of the straight-A students are Vietnamese, but, at the same time, the Vietnamese dropout rate is double the rate for all students. The deep alienation of some young Vietnamese was dramatized last month when four teen-agers, considered ordinary kids, took hostages for reasons known only to themselves in a Sacramento appliance store -- shouting that they wanted to go back to Vietnam and hunt communists -- and killed three people before being gunned down themselves by police.
''These teen-agers rebel,'' said a policeman in Westminster of local gang members. ''They say, 'I tried to be a Vietnamese and it didn't work. I tried to be an American and it didn't work. So now I'm a gangster.'''
Vietnamese-Americans have great trouble working a lot of this out because they face the same travel restrictions to the land of their birth as other Americans; making arrangements in the United States is considered a violation of the Trading With the Enemy Act of 1917. The principal link for many of them, perhaps even most, is sending money to relatives. The ignorance of the country's communist rulers, combined with American-enforced international sanctions and boycotts, is creating a generation of new casualties on both sides of the Pacific, in a war that was supposed to have ended more than 15 years ago.
*Richard Reeves is a syndicated columnist.