Matthew Diaz felt morally obligated. If he didn't tell, who would?

Diaz, a Northwest Indiana native, felt in 2005 that he needed to use his access as a Navy lawyer at Guantanamo Bay, Cuba, to give out a government secret: the names of 551 men imprisoned at Guantanamo.

The U.S. Supreme Court had ruled the prisoners had a right to challenge their detention in U.S. courts, but Pentagon officials were withholding the names from lawyers who might file petitions on the prisoners' behalf.

So Diaz packed a list of names into a Valentine's Day card and mailed the card to a New York lawyer.

Three years later -- and after a six-month stay in the Navy brig -- Diaz still believes he was right. Others agree. He was in Washington, D.C., on Wednesday to accept a Ridenhour Prize, which places him alongside famed journalists, activists and President Carter.

Diaz, 42, said he thinks the country is moving back toward caring about constitutional rights.

"I hope we're going back and not unraveling too far from the core," Diaz said.

Diaz was born in Gary, and he lived in Hammond, Merrillville and Crown Point before he moved to Walkerton, Ind., in sixth grade, and later to California. His mother, Eleanor Sierkowski, still lives in Merrillville.

Diaz served in the Army, earned a law degree and joined the Navy's Judge Advocate General Corps. He went to the Cuba base as a JAG lawyer in 2004. The camp holds detainees linked by the government -- correctly or falsely -- to the fight against terror.

After the Supreme Court ruling, military officials created parole-style boards to see detainees, but little information was released on the detainees.

In secret, Diaz sent the names to a New York lawyer. But the lawyer consulted a judge, and a federal investigation started. Diaz was convicted in military court in May 2007 of several charges, sentenced to the brig and dismissed from the military. He expressed regret at trial.

The Pentagon later released the detainees' names to The Associated Press after an open records request.

Diaz, now of Jacksonville, Fla., did his time in the brig, but he has appealed his conviction and his dismissal. A pension is at stake, and he wants the conviction overturned, he said. He is hoping for the best and preparing for the worst, he said.

He has been judged a traitor by bloggers in the unforgiving, multi-jurisdictional court of the Internet. But Diaz feels the names had to be released. He is "humbled" to receive the Ridenhour Truth-Telling Prize, he said. The awards are named for Richard Ridenhour, the soldier who wrote a letter to Congress in 1969 detailing the My Lai massacre in Vietnam.

Once he is done fighting his conviction and dismissal, Diaz wants to teach elementary school.

His mother -- who attended the ceremony with him -- is proud. A lot of people wanted the Guantanamo names released, Sierkowski said.

"My son just happened to speak up about it, and he's in this situation."