Obama wins Wis. for 9th straight triumph

In a race growing increasingly negative, Obama cut deeply into Clinton's political bedrock in Wisconsin, splitting the support of white women almost evenly with her. According to polling place interviews, he also ran well among working class voters in the blue collar battleground that was prelude to primaries in the larger industrial states of Ohio and Pennsylvania.

Clinton made no mention of her defeat, and showed no sign of surrender in an appearance in Youngstown, Ohio.

"Both Senator Obama and I would make history," the New York senator said. "But only one of us is ready on day one to be commander in chief, ready to manage our economy, and ready to defeat the Republicans. Only one of us has spent 35 years being a doer, a fighter and a champion for those who need a voice."

In a clear sign of their relative standing in the race, most cable television networks abruptly cut away from coverage of Clinton's rally when Obama began to speak in Texas.