WASHINGTON — With no end in sight, Democrats braced Wednesday for a prolonged and nasty fight for their party's presidential nomination as Barack Obama assailed his reinvigorated rival over taxes and, in a turnabout, her experience in foreign affairs.
Hillary Rodham Clinton, in turn, renewed her assault on Obama's resume and preparedness for the White House, a line of fire that helped produce three back-to-the-wall victories that saved her campaign from extinction Tuesday.
Even with her hard-fought victories in the Ohio, Texas and Rhode Island primaries, Clinton barely narrowed Obama's lead in delegates to the party's national nominating convention. The party's proportional system for awarding delegates gave Obama fresh batches in each state, bolstering his claim to front-runner status.
Obama also won Vermont's primary and appeared to be well ahead of Clinton in the Texas caucus that followed that state's primary, ensuring him an additional trove of delegates when the results are finalized over the next few days.
Despite Obama's sustained delegate edge, there was an unmistakable shift in momentum as Clinton strategists crowed over their victories.
Obama, in a news conference, displayed a new willingness to attack, even as his opponent entertained the idea of the two running on the same ticket in November.
The Illinois senator suggested that the media should be tougher on his opponent, the same case Clinton was making 48 hours earlier.
On a morning flight from San Antonio to Chicago, Obama let loose on Clinton for suggesting she was more seasoned in foreign affairs.
"I have not seen any evidence that she's better equipped to handle a crisis," he told reporters just before takeoff. "If the only criteria is longevity in Washington, she's certainly not going to beat John McCain on that."
The new sniping between Obama and Clinton came as McCain, the presumptive Republican nominee, sat down at the White House for a hot-dog lunch with President Bush, followed by an endorsement in the Rose Garden.
The bitterness of the Democrats' race sparked questions on whether it might undermine the eventual nominee, enabling the Arizona senator to raise money and rally Republicans while Clinton and Obama effectively did his dirty work.
William Galston, a senior fellow at the Brookings Institution and former Clinton White House official, suggested that the general-election defeats of Gerald Ford in 1976 and Jimmy Carter in 1980 should give Democrats pause.
