WRAPUP 4-Clinton, Obama sharpen their attacks

By Claudia Parsons

PROVIDENCE, R.I., Feb 24 (Reuters) - Democratic presidential hopefuls Hillary Clinton and Barack Obama sharpened their attacks on each other on Sunday, trading barbs over health care, trade and experience as they head for key showdowns in Texas and Ohio on March 4.

As Obama tried to nail down the Democratic nomination by winning those two states and Clinton battled to say alive, a familiar face joined the presidential race. Consumer advocate Ralph Nader, blamed by many Democrats for their 2000 White House loss, said he would run again as an independent.

Clinton, who trails Illinois Sen. Obama in delegates to this summer's national convention that will pick the Democratic candidate for the November election, needs wins in both states to keep her campaign afloat.

Clinton mocked Obama's speeches in which he emphasizes hope and promises change, telling supporters the problems facing the next president would not be easily solved.

"I could just stand up here and say 'Let's just get everybody together, let's get unified.' The sky will open, the light will come down, celestial choirs will be singing and everyone will know we should do the right thing and the world will be perfect," she said at a rally in Providence, Rhode Island.

Obama fired back in Lorain, Ohio, criticizing the New York senator for changing her position on the North American Free Trade Agreement pushed through by her husband, former President Bill Clinton.

"She has essentially presented herself as co-president during the Clinton years," he said. "So the notion that you can selectively pick what you take credit for and then run away from what isn't politically convenient, that doesn't make sense."

With the economy a key issue in the U.S. presidential race, Obama has turned trade into a centerpiece of his campaign in Ohio, where trade agreements are particularly unpopular as domestic manufacturing jobs disappear.