Juan Mendez was arrested in 1975 in Argentina, and says he was tortured with electric shock and jailed a year and a half before being allowed to leave the country. Alicia Partnoy, a politically active college student, was jailed for 3 1/2 years by the military authorities, much of the time, she says, being regularly threatened with death.

Both Mendez, 37, and Partnoy, 27, along with perhaps 250,000 other Argentines, now live in the United States, holding only bitter memories of the military government that rules their homeland. Yet along with the vast majority of Argentines here and in Argentina--and against the prevailing American opinion--Mendez and Partnoy firmly support the Argentine invasion of the Falkland Islands, no matter who ordered it or why.

Argentines all over the world feel about the Falklands, which they call the Malvinas, as Texans feel about the Alamo, a historic outrage to be avenged. "A hundred percent of Argentines, including those in exile in America, agree that the Malvinas are in Argentine territory and we have a right to be there," said Mendez, an attorney who originally was arrested for defending political prisoners.

A few Argentines here do not support the island invasion with such confidence. Jose Siderman, a 71-year-old businessman forced to flee his country in 1976 after his arrest by the military in Tucuman, said, "As an Argentine, I'm embarrassed that the government took that kind of action." He thinks the dispute should be settled by negotiations. But other Argentines, even those most critical of the Buenos Aires government's human rights abuses, brush that argument aside.

"I agree with all the opposition political parties who support the government having taken the Malvinas for Argentina," said Partnoy, now a receptionist at an embassy in Washington. She does not feel that the government should negotiate a further settlement of the dispute "without letting the people decide what should be negotiated."

And if there is anything that annoys her about the Falklands dispute, it is, ironically, the sudden attention paid in the world press to Argentina's human rights violations. "I feel a little bit angry that now is the time people discover there is a dictatorship in Argentina, when it has been there for six years," Partnoy said.

Larry Birns, director of the nonprofit Council on Hemispheric Affairs in Washington, said he was not surprised that the many Argentines in the United States support the Falklands takeover. "There is a very high degree of nationalism in Argentina. I have seen Jewish families that have migrated from Russia and in 30 years they have become completely Argentine," he said.

The rapidly worsening economy, as well as the increasing political persecution in the mid-1970s, forced many Argentines to leave the country. Mendez said Argentine officials have estimated that as many as 2 million of the country's 27 million people may have left in the last two decades.

Argentines coming to the United States have tended to be apolitical and unwilling to speak out against the government because relatives remained behind. Siderman, a success in the construction and appliance business in Argentina, was kidnaped by leftists in 1974 and by rightists in 1976 and said he wanted just to establish a business when he arrived in Los Angeles. But the Argentine government, apparently determined to take over the $25 million in property he left behind, went to great lengths to harass him , he said.

When Siderman was visiting relatives in Italy, he was arrested on an Argentine warrant for alleged passport violations. The action forced him to spend nearly seven months in Italy last year, much of the time in jail, before Italian authorities threw out the charges.

Siderman, now outspoken about his opposition to the Argentine government, agrees with many Argentines here that the Falklands takeover was designed to distract the Argentine people from the worsening economy.

Mendez recalls a brief, celebrated escapade by a small group of Argentines, led by a man named Dardo Cabo, who hijacked a plane and briefly raised the Argentine flag over the Falklands in the early 1960s.

Cabo became a hero but he was also an ardent Peronist, and the military authorities jailed him in the mid-'70s. Mendez recalls he was at the same prison as Cabo, "before they took him out and killed him."