Jeremiah Denton, 89, famed Vietnam POW

Prisoner of war Jeremiah Denton declared his loyalty to the U.S. government during a 1966 interview for what was supposed to be a propaganda film. But his enraged captors missed his more covert message: "T-O-R-T-U-R-E," blinked into the camera in Morse code, a dispatch that would alert the U.S. military to the conditions he endured.

Mr. Denton, who would survive 71/2 years confined in a tiny, stinking, windowless cell at the infamous "Hanoi Hilton" and other camps before his release in 1973, died of heart problems Friday in Virginia Beach, Va., at age 89, his grandson Edward Denton said.

The elder Denton later became the first Republican from Alabama elected to the Senate since Reconstruction, though the iron will that allowed him to persevere in captivity gave rise to criticism that he was too rigid a politician.

In July 1965, a month after he began flying combat missions for the Navy in Vietnam, the Mobile native was shot down near Thanh Hoa. He was captured and recalled his captivity in a book titled When Hell Was in Session.

"They beat you with fists and fan belts," he told the Los Angeles Times in 1979. "They warmed you up and threatened you with death. Then they really got serious and gave you something called the rope trick." The use of ropes - to cut off circulation in his limbs - left him with no feeling in his fingertips and intense muscle spasms, he said.

Some of the most severe torture came after the 1966 interview, in which he confounded his captors by saying that he continued to fully support the U.S. government, "and I will support it as long as I live."

The tape was widely seen, and U.S. intelligence experts had picked up the Morse Code message. But Mr. Denton theorized later that his captors likely figured it out only after he was awarded the Navy Cross - the second-highest decoration for valor - for the blinks in 1974.

His words and bearing, beamed back to his country by television, gave heart to the military at a time of increasing uncertainty and bitter division over the course of the war.

He was promoted to rear admiral and retired from the Navy in November 1977. Mr. Denton then turned to politics, despite having no experience running for a statewide political office. With Ronald Reagan atop the GOP ticket, Mr. Denton became the first Republican elected to the Senate from Alabama since the Reconstruction era following the Civil War.

"The valor that he and his fellow POWs displayed was deeply inspiring to our nation at the time, and it continues to inspire our brave men and women who serve today," President Obama said in a statement. "As Senator, he served as a strong advocate for our national security. He leaves behind a legacy of heroic service to his country, and Michelle and I send our condolences to the Denton family."