There are increasingly few people who can talk about their memories of the camps, which began in 1942 and officially existed for more than four years. Mr. Takei and his contemporaries were young children at the time that President Franklin D. Roosevelt issued the executive order after the attack on Pearl Harbor.

Most of the people who were in the internment camps during the Second World War have died, including Fred Korematsu, the Oakland native who defied incarceration orders and was convicted of disobeying a military order. Mr. Korematsu appealed to the Supreme Court, which upheld the internment with a 6-3 ruling, saying the policy was justified to protect national security during a wartime emergency.

Mr. Korematsu’s daughter, Karen Korematsu, said she had gone from stunned to sad to outraged since the ruling. Along with other children of those who had been in the camps, Ms. Korematsu submitted an amicus brief this year arguing against the ban.

“I thought oh my gosh, Daddy would be so sad to know this,” she said. “They really took Korematsu vs. U.S. in vain. My father would have felt the same way. They overruled his case in the face of marginalizing other people. That’s certainly not what he would have wanted to see happen.”

Ms. Korematsu runs an educational institute in her father’s name in San Francisco and has received several celebratory messages since the ruling, she said, but she has answered nearly everyone the same way: “We have a lot of work to do. All we have done is to trade one injustice for another. This is not a time for celebration, this is a time to dig deep and to regroup and figure out what our next steps are.”

Larry Oda, who was born in a camp in Crystal City, Tex., said today’s court applied the same logic that it used to justify holding his parents.