SAN FRANCISCO  Lawrence Lessig, the Web legal scholar, said Wednesday that he was mulling a campaign for the House of Representatives, a move that could pit the Internet icon in a race against a Democratic loyalist.

Mr. Lessig would run for the seat left vacant by the Feb. 11 death of Representative Tom Lantos, who represented the 12th District of California for nearly 14 terms. The district, south of San Francisco, runs straight through the heart of Silicon Valley, where Mr. Lessig is considered a celebrity, though one who wears glasses and uses phrases like “net neutrality.”

On Wednesday, Mr. Lessig’s quasi-announcement was made, not surprisingly, in a posting on his blog and an accompanying 10-minute Web video.

“It is very rare to have the chance to live in times where there’s the opportunity for fundamental change; this is one of those times,” said Mr. Lessig, a Stanford professor who is the founder of the Center for Internet and Society at the university. “We need to fix Washington now.”