Obama and Clinton mix civility and barbs in final debate before Super Tuesday contests

Democrats Barack Obama and Hillary Rodham Clinton sparred over immigration, health care and the war in Iraq in their first one-on-one debate ahead of almost two dozen primary contests this Tuesday.

On the Republican side, Sen. John McCain added to his momentum going into Super Tuesday, picking up a key endorsement from California Gov. Arnold Schwarzenegger on Thursday. His main rival, former Massachusetts Gov. Mitt Romney, promised to fight aggressively for the Republican nomination.

At the Democrats' debate Thursday night, Obama and Clinton alternated between civility and pointed swipes, underscoring the importance of the upcoming contests.

Clinton emphasized that the country needs a president ready to go to work on "Day One." Obama responded: "Part of the argument that I'm making in this campaign is that it is important to be right on Day One."

Obama appears to have most of the momentum as of now, including high-profile endorsements and impressive fundraising. But Clinton has considerable institutional strength and is still widely favored to do better overall than Obama on Super Tuesday.

But neither senator is expected to clinch the Democratic nomination this Tuesday, due to the close race and party rules that do not permit "winner take all" state contests like the Republicans have.

Obama's campaign reported raising a staggering $32 million (euro21.5 million) in January, cash aplenty to advertise all through the nearly two dozen upcoming races from coast to coast - and contests beyond.

Clinton's campaign reported raising $26.8 million (euro18 million) from October through December, the most recent period she reported.

Los Angeles, Friday, AP