They defected from a country that no longer exists.

None regrets the decision. All believe it contributed to the destruction of the Soviet Union and its Marxist-Leninist underpinnings. But most won't go back to live there and savor the fruit of their sacrifice."You become a slave of mortgage, college tuition," said Alexandra Costa, a mother of two who defected in 1978 from the Soviet Embassy here. She would like to go back and help Russia on its road to democracy, "but I can't afford to."

Costa, like many of the hundreds of Soviet citizens who defected during the 40-year Cold War, still uses an assumed name and has an unlisted number.

Many defectors still refuse to say where they live or to have their pictures taken. A few have had their faces altered.

But all - KGB officers, Communist Party officials, musicians, truck drivers - have adopted the United States as their home.Victor Gundare

Victor Gundarev defected from his post as deputy chief of the KGB station in Athens in 1986. His motives were professional and personal.

He had blown the whistle on corruption and embezzlement at the KGB - "I tried to start perestroika at the KGB" - and was having serious marital problems.

The CIA whisked him, his girlfriend - now his wife - and his son out of Greece. In the United States he was questioned for several months, moved to another city and given a new identity.

Settling in was hard. At one point he was so angry with the CIA - accusing it of reneging on promises to provide him and his family with citizenship - that he considered returning to the Soviet Union.

He went as far as meeting with Soviet officials - in the safety of the State Department - who promised that all would be forgiven if he went back. The final meeting took place last year, before the Soviet Union died.

Now, he won't hear of going back.

"My son is 75 percent American, 25 percent Russian," Gundarev said in a telephone interview from his home somewhere in the United States, from where he serves as a consultant to American firms.

He'd like to return for a visit, to see friends and explain how he believes his defection ultimately helped free them from totalitarianism.

But not for a while. He still doesn't feel safe about going home.Stanislav Levchenko

Before Stanislav Levchenko can even consider a visit, he must find out whether the death sentence issued against him in absentia is still in force.

Levchenko, a former KGB major, defected from his post as an agent in Japan 11 years ago. He now lives in suburban Virginia.

"I have no doubt I did what I could to accelerate the disintegration of the system," the stocky one-time spy said in fluent but heavily accented English. He has written several critical works about the KGB, some of which were translated into Russian.

His decision was not without cost. He left behind a teenage son who only now, after intense lobbying from Washington, is being allowed to join him. Soviet authorities prevented the youth from getting a college education because of his father's defection, Levchenko said. His ex-wife is also being allowed out, he said.Alexandra Costa

Levchenko's second wife is Alexandra Costa.

They met at a World War III simulation game conducted by a Washington-area think tank - they were both on the Red team (the Russians) which beat the Blue team (the Americans).

They made such a good team they decided to get married.

She had been living underground for seven years, ever since she took her two toddlers and left her husband - a first secretary at the Soviet Embassy - to go into the FBI's protective custody in 1978.

Her husband went back to Moscow and was cleared of wrongdoing. His career took off but he hasn't been in touch with the family since, she said. She never wants to see him again - except maybe once, if she could bring him to their son's high school football game "to see what he missed."Alexander Ushakov

Alexander Ushakov is one of the few defectors who has few qualms about going back - for good.

Ushakov has been invited by the Russian parliament to help implement an agricultural reform plan he devised and which was adopted into law last year. The plan is based on the 1862 American Homestead Act - "a holy text," he says - which granted the right to individuals to own land.

He was a naval commander who taught Marxist philosophy at the Naval Academy in Odessa. But he didn't practice what he preached.

"My goal was not to shake the system," he said in an interview. "It was to destroy it."

In 1984 he was arrested for his anti-Marxist views, his writing seized, and he was sentenced to 12 years of jail and internal exile.

He escaped. Of the estimated 2,000 Soviets who tried every year to cross the mountains into Turkey, only one or two made it. Ushakov was one.

He left his wife behind but managed to get her out four years later. She is now pregnant with their first child. He also left behind two children from his first marriage.

With the Communist Party and the KGB in tatters, Ushakov feels he can go back.

But the United States is home now. "I consider this country as mine," he said. "When something goes wrong, I feel pain. When something good happens, I feel happiness."