Fred Korematsu, 86, the Japanese American whose court case over his refusal to be interned during World War II went to the U.S. Supreme Court and became synonymous with this nation's agonized debate over civil liberties during time of war, has died.

Mr. Korematsu died Wednesday of respiratory illness at his daughter's home in the Northern California community of Larkspur, according to his attorney, Dale Minami.

In February 1942, 120,000 U.S. residents of Japanese ancestry — both citizens and noncitizens — were ordered into internment camps following Japan's Dec. 7, 1941, attack on Pearl Harbor. Mr. Korematsu did not turn himself in and was arrested, jailed and convicted for failing to report for evacuation.

Mr. Korematsu was one of several who challenged the constitutionality of President Roosevelt's Executive Order 9066 authorizing internment. His case eventually reached the U.S. Supreme Court and, in 1944, the court upheld the order. But, as was discovered many years later, the court — and the nation — had been gravely misled about the potential dangers from Japanese Americans.

Indeed, Mr. Korematsu's case was cited as recently as April 2004. At issue before the Supreme Court was whether U.S. courts could review challenges to the incarceration of mostly Afghan prisoners held at Guantánamo Bay Naval Station in Cuba in the aftermath of the Sept. 11, 2001, terrorist attacks.

Mr. Korematsu, then 84, filed a friend-of-the-court brief saying, "The extreme nature of the government's position is all too familiar."

Last June, the U.S. Supreme Court ruled that the Bush administration's policy of detaining foreign nationals without legal process at Guantánamo Bay was illegal.

Mr. Korematsu's case was reopened in the 1980s when historian Peter Irons found documents indicating the government lied to the Supreme Court, a lie that would provide the basis for a landmark 1983 federal-court decision to vacate his conviction.

Fred Toyosaburo Korematsu was born Jan. 30, 1919, in Oakland, Calif., where his parents, who were born in Japan, ran a plant nursery. After graduating from high school, he was working as a welder when Japan's attack on Pearl Harbor plunged the United States into war.

Official concerns that Japan would find sympathizers in the Japanese-American community on the West Coast surfaced, including the idea that there might be an effort to get messages to Japanese submarines offshore.

The following February, Roosevelt granted broad powers to the War Department to carry out internment, acting upon the assertions of Gen. John DeWitt, the Army general in charge of the West Coast, who believed that Japanese Americans were more loyal to Japan than to the United States. Mr. Korematsu, then 22, did not go to the camp, and on May 30, 1942, was arrested.

As his case moved through the courts, Mr. Korematsu lost at every turn, including in the U.S. Supreme Court in 1944.

During research in 1981, historian Irons found mislabeled and misplaced records, including a memo from a Justice Department lawyer to U.S. Solicitor Gen. Charles Fahy, the person responsible for arguing the government's side in cases before the Supreme Court. In the memo, the Justice Department accused Fahy of lying to the Supreme Court.

In one example, the Justice Department strongly disputed the basis of DeWitt's claim that people whose ancestry was Japanese were engaging in "extensive radio signaling and in shore-to-ship signaling" to Japanese ships. Such activity had formed a primary basis for the internment.

But, the Justice Department memo asserted, DeWitt in fact had no evidence that overt acts of treason were being committed. There were some indications that the "signaling" was nothing more than kids going to outdoor toilets at night with flashlights.

In the final briefs filed with the high court, however, the Justice Department's views were diluted to such an extent that the Supreme Court could hardly have determined their meaning.

Irons contacted Mr. Korematsu as well as former University of Washington student Gordon Hirabayashi, who had gone to prison rather than obey curfew and evacuation orders, and Minoru Yasui, who had served time for violating the curfew. All three cases had reached the Supreme Court in the 1940s and all three had lost.

At a November 1983 hearing for Mr. Korematsu, U.S. District Judge Marilyn Hall Patel said she would vacate the conviction and make formal findings of fact that the government was in error — everything Mr. Korematsu's attorneys had asked for.

Yasui's conviction was vacated in 1984. Hirabayashi's conviction was vacated in 1987 by the 9th U.S. Circuit Court of Appeals, which found that the government had engaged in "suppression of evidence" in its presentation of his original case to the Supreme Court.

In 1971, Congress repealed the law under which all three had been convicted. Five years later, President Ford acknowledged that the internment had been a "national mistake," and, in 1983, a federal commission unanimously concluded that the factors that shaped the internment decision were "race prejudice, war hysteria and a failure of political leadership" rather than military necessity.

President Reagan in 1988 signed legislation authorizing reparations of $20,000 each to thousands of surviving internees, including Mr. Korematsu. In 1999, President Clinton awarded Mr. Korematsu a presidential Medal of Freedom, the nation's highest civilian honor.