That was only part of the problem. The company’s top executives were engaging in activities that the Securities and Exchange Commission and federal prosecutors said were improper. His immediate boss, Andrew Feldman, ultimately pleaded guilty to a felony count of violating internal accounting controls, and Mr. Feldman and four other top executives agreed to an S.E.C. settlement in a complaint accusing them of a scheme to defraud investors by misstating revenues.

Mr. Wu was untouched by the investigations, but said he had known that things weren’t right.

It all crystallized for him on Sept. 12, 2001 — the day after the 9/11 attacks. He was stranded in Atlanta at a trade show with other company employees. Their business engagements were canceled because of the attacks, and, with no other plans, his colleagues decided to go to a strip club. On such a solemn day, the tawdry revelry repelled him.

“I wondered how I’d gotten there,” he recalls. “I realized that what we’d been doing all those months was abhorrent.” He had been living in a world based on nothing but money, he said, and saw that “the idea that the private sector, the free market, on its own has all the solutions is just a myth.” He added: “When it’s just about money, there are no values.”

He looked for a way out and got a job teaching law at the University of Virginia. But the Internet preoccupied him. “I thought of it as a kind of perpetual frontier, the place where everyone gets a shot, where the underdogs have a chance. The Internet has been that. And I wanted some principles that would keep it that way.”

He got back in touch with Mr. Lessig, who encouraged him in May 2002 to put his thoughts down on paper. The result was a sparkling memo, “A Proposal for Network Neutrality,” that asked: “What principle can balance the legitimate interests of broadband carriers in administering their networks with the danger of harm to new application markets? And how can such a principle be translated into both clear legal guidelines and the practice of network design?” The answer was in the title: a new creation called network neutrality. Mr. Lessig began sending the paper to his contacts the next month.

Mr. Wu’s ideas spread, reaching top staff members at the F.C.C., who brought them to the attention of Michael Powell, then the commission chairman.