About 2,000 foreign nationals in indefinite detention around the country, including 700 to 1,000 Mariel refugees from Cuba, must be released as a result of a U.S. Supreme Court decision Wednesday.

The 7-2 ruling, written by Justice Antonin Scalia, struck down one of the last measures used by the government to hold the migrants, who are convicts, without any hope of release. Justice Clarence Thomas and Chief Justice William Rehnquist dissented.

The ruling was not a total surprise. Most immigration-law experts had expected the Supreme Court to follow its 2001 rejection of indefinite detention for those who could not be deported because their countries would not take them back.

Despite the 2001 ruling, the government continued to hold the group of Mariel refugees by claiming, under a complicated immigration-law theory, that they had never ''technically'' entered the United States. The government classified those refugees as ''excludable'' and ''inadmissible'' because they had been convicted of crimes and their immigration paroles were revoked.

Scalia, in Wednesday's majority opinion, indicated that the government misinterpreted the high court's 2001 opinion, which said the government could hold deportable foreign nationals for no more than six months.

Justice Sandra Day O'Connor, in a concurring opinion, wrote that the government could detain foreign nationals for more than six months as long as it had ``reasonable grounds to believe an alien has engaged in certain terrorist or other dangerous activity.''

In his dissent, Justice Thomas said that migrants deemed ''inadmissible'' do not have the same constitutional rights as other migrants. He also said that the 2001 ruling rejecting indefinite detention was wrong.

Many Mariel refugees were classified as ''excludable'' after the 1980 boatlift from the Cuban port of Mariel, but the majority were paroled, and most obtained permanent U.S. residence and citizenship.

A few, however, were convicted of crimes here and were deemed ``excludable.''

One of them was Daniel Benítez, a Hialeah resident, whose case was one of two that the high court reviewed to make its decision Wednesday.

Benítez sought a green card in 1985. He was rejected because he had been convicted of grand theft in Florida. He was subsequently convicted of additional felonies, including armed robbery, armed burglary, aggravated battery and unlawful possession of a firearm.

His immigration parole was revoked in 1993, and he was ordered deported in 1994. But Cuba would not take him back.

Federal authorities transferred him to a halfway house in Miami by the time the Supreme Court heard oral arguments in the case last Oct. 13. He was released a few days later, moved in with his brother in Hialeah, and began to work as an electrician's assistant.

Although free, Benítez could have been put back in indefinite detention had the Supreme Court not ruled as it did. Benítez can still be detained if he violates parole conditions, if he is convicted of a new felony, or if political conditions change in Cuba and Havana agrees to take back Cubans ordered deported by the United States.

The 700 to 1,000 Mariel refugees still in custody are in federal prisons across the country. Benítez was last held at a facility near Denver. It is unclear if any indefinitely detained migrants are held in South Florida, although no known cases have surfaced locally in recent years.

''I think this is a victory for Jehovah God, who gave us freedom and the right to be free,'' Benítez, a Jehovah's Witness, told The Herald in a telephone interview from the office of Miami lawyer Emilio de la Cal.

John Mills, a Jacksonville lawyer who argued the case before the Supreme Court, said the ruling ``prevents the president and the executive branch from abusing their authority and arbitrarily depriving a human being of his liberty.''

Judy Rabinovitz of the American Civil Liberties Union, who championed the cause of indefinitely detained Mariel refugees, welcomed the ruling.

''It's a vindication of the position we've taken all along, that the government was violating the court's [2001] decision by continuing to detain these individuals,'' she told The Herald.

''It's good to know that, in the face of 9/11, the Supreme Court won't hesitate to issue a just ruling on behalf of immigrants,'' said Cheryl Little, executive director of the Miami-based Florida Immigrant Advocacy Center.

The government's Department of Homeland Security has yet to announce how it will proceed with releases in the cases affected by Wednesday's ruling. Each case, however, would be handled individually.

THE STORY SO FAR
• The 1980 Mariel boatlift brought more than 125,000 Cuban refugees to U.S. shores. While most became legal residents or citizens, several hundred had their parole revoked and were classified as ''excludable'' or ''inadmissible'' as a result of criminal convictions.

• As such, ''inadmissible'' or ''excludable'' migrants were deemed ''stopped at the border'' and thus without the same due-process rights of immigrants who entered the country legally or illegally.

• In 2001, the U.S. Supreme Court ruled that admitted migrants could not be held indefinitely. The government carved out an exemption for ''excludable'' and ''inadmissible'' foreigners who continued to be held after they finished serving sentences.

• On Wednesday, the high court struck down that interpretation and said convicted Mariel refugees and other ''inadmissible'' or ''excludable'' migrants cannot be held permanently.