By John Whitesides, Political Correspondent
WASHINGTON (Reuters) - Hillary Clinton refused to countherself out of the U.S. presidential race on Tuesday as herhard-fought duel with Barack Obama for the Democraticnomination rested with voters in Ohio and Texas.
Turnout was expected to be strong in states -- Ohio, Texas,Vermont and Rhode Island -- voting on Tuesday. Polls close inOhio at 0030 GMT on Wednesday and all voting in Texas will beover by 0200 GMT on Wednesday.
The first results could be available immediately after thepolls close, although a very tight race could take hours.
Clinton, a New York senator battling to snap Obama's stringof 11 state-by-state victories, needs wins in both Ohio andTexas to rejuvenate her campaign and justify keeping theDemocratic race alive until the next delegate-rich prize --Pennsylvania -- votes on April 22.
Losses in even one of Tuesday's states could set off astampede of party support for Obama, raise pressure on Clintonto drop out and make it even tougher to cut Obama's lead in thepledged delegates who will choose the Democratic nominee tocontest November's presidential election.
Tuesday's contests also could put Arizona Sen. John McCain,the Republican front-runner, close to clinching his party'snomination. McCain is favoured to beat his last major rival,former Arkansas Gov. Mike Huckabee, in all four states.
"I believe that with your help today that we can secureenough delegates to make sure that we can secure thenomination, but we have to win and we have to win big here inthe state of Texas," McCain told supporters in San Antonio.
TIGHT RACES
Opinion polls show Clinton and Obama in tight races in bothOhio and Texas -- the biggest prizes on Tuesday.
The former first lady, who would be the first female U.S.president, refused to mull how she would respond to a loss.
"I don't think like that. We're working hard," Clinton toldreporters after greeting voters at a school. "We think we'regoing to do really well here in Texas and in Ohio."
Clinton had a slim lead in Texas over Obama, an Illinoissenator who would be the first black president, and pulled evenin Ohio, according to a Reuters/C-SPAN/Houston Chronicle pollreleased on Tuesday.
She took a 47 percent to 44 percent lead on Obama in Texas,reversing his 3-point edge in the poll on Monday. The lead waswithin the poll's margin of error of 3.4 percentage points.
The Ohio race was deadlocked at 44 percent in the pollingby Zogby International, a slight gain for Clinton from Obama's2-point edge on Monday.
Obama stopped by a rodeo in Houston to check out sometractors and livestock and shake hands with potential voters.He made few comments except to say "I feel good."
Clinton's campaign aides have been tamping downexpectations, easing away from talk that she needed to win bothOhio and Texas, with their combined 334 delegates at stake.
Obama noted the high stakes in a rally on Monday night.
"So here we are with the possibility of winning thenomination," Obama said in Houston. "One of the things thatI've learned is that what makes this powerful is not thatthings always go easy, but rather that we are willing to goforward when it's hard."
Like her husband, former President Bill Clinton, whonicknamed himself "The Comeback Kid" for his improbable rise tothe White House in 1992, Clinton has dodged disaster before.
In January, Obama appeared ready to deal her a knockoutblow in New Hampshire after his big win in Iowa, but she defiedopinion polls and won the victory.
After a landslide loss in South Carolina, Clinton battledObama to a draw in Super Tuesday contests around the country onFebruary 5, winning some of the biggest prizes of the night inCalifornia, New York and New Jersey.
Under Democratic rules allowing the losers in each state towin a proportional amount of delegates, Clinton cannot closethe gap on Obama among pledged delegates unless she scores bigwins in Ohio and Texas that appear beyond her grasp.
An MSNBC count gave Obama 1,194 delegates to Clinton's1,037 before Tuesday's showdowns, well short of the 2,025needed to win the nomination.
(Additional reporting by Ellen Wulfhorst, Caren Bohan andJeff Mason in Texas, Writing by Deborah Charles, editing byPatricia Zengerle)
(For more about the U.S. political campaign, visit Reuters"Tales from the Trail: 2008" online athttp://blogs.reuters.com/trail08/)
