(Alex Wong/Getty Images)

On Wednesday, the Pentagon lost perhaps its foremost thinker on cyber warfare, Gen. James E. Cartwright, who is retiring as vice chairman of the Joint Chiefs of Staff after 40 years of service in the Marines.

At a farewell ceremony under a gray, drizzly sky at the parade field of the U.S. Marine Barracks, Defense Secretary Leon Panetta and his outgoing deputy, William J. Lynn III, paid tribute to an officer Panetta called “one of the military’s most original thinkers,” who “possesses a unique blend of technical and strategic brilliance.”

Cartwright had a reputation for his analytical prowess, but also for his independent streak. A willingness to challenge the conventional wisdom inside the Pentagon earned him critics, some of whom waged a concerted campaign to lobby President Obama to bypass him as chairman of the Joint Chiefs.

Still, Lynn noted, Cartwright was widely respected for pushing for what he thought was right, on matters large and small. When Cartwright was told it was not possible to have an iPad certified to hold classified intelligence, the Marine general picked up the phone and called the Defense Advanced Research Projects Agency. A few days later, he had his iPad.

“He jolted the system,” Lynn said, “speeding the adoption of information technology across the force.”

“Hoss,” as Cartwright was known, was determined “not to conduct business as usual,” Panetta said. “He challenged positions. He was not afraid of a contrary view.”

Lynn and Cartwright guided the preparation of the Pentagon’s first ever cyber strategy, released last month. Cartwright also devised the conceptual framework for tackling the threat, and identified the organizational changes it called for within the Pentagon and the services.

Forty years ago, Cartwright left an Iowa farm to join the Marines at the height of the Vietnam War. He rose to become head of U.S. Strategic Command, where he worked to develop new strategies to tackle cyber, nuclear proliferation, space and missile defense issues.

“He saw [the use of cyber space] as a major emerging threat…and put STRATCOM on a footing to deal with cyber as a major strategic issue,” Sen. Dianne Feinstein (D-Calif.) said in a statement.

Panetta said that, when he was CIA director, Cartwright was the first person he turned to for guidance on how to reel in Osama bin Laden after receiving intelligence reports on the al-Qaeda leaders’s whereabouts in Abbottabad.

Cartwright “was instrumental in helping us to plan and execute the operation that took bin Laden down,” Panetta said.

Displaying his self-deprecating wit, Cartwright joked that he “wouldn’t have it any other way than to be raining.”

He read from a speech Teddy Roosevelt gave in 1910, whose words, he said, have guided him.

“It is not the critic who counts…. The credit belongs to the man who’s actually in the arena, whose face is marred by dust, and sweat and blood. …Who at best knows in the end the triumph of high achievement, and who at worst, if he fails, at least fails while daring greatly. So that his place shall never be with those cold and timid souls, who know neither victory nor defeat.”

Cartwright stressed that leaders have “a moral obligation” to take care of their servicemen and women -- and not just in battle, “but all through their lives and all through our own lives.”

“Today,” he said, “my last salute is in honor of all who have served, all who are serving and all who will serve.”