Ohio, Texas primaries: End of the road for Clinton?

Voting ends in Ohio at 7:30 p.m. EST 0030 GMT on Wednesday and all voting in Texas will be over by 9 p.m. EST 0200 GMT on Wednesday.

Clinton8217;s husband, former President Bill Clinton, has said she needs to win both states to continue her campaign, a view shared by many analysts. Polls show tight races in both.

Even a split decision in the two states would leave her with a steep climb to overtake Obama8217;s lead of roughly 150 pledged convention delegates who select the nominee, and increase the pressure on her to quit.

8220;There will be people in her campaign who will argue a split decision is good enough to continue,8221; said Cal Jillson, a political scientist at Southern Methodist University in Dallas. 8220;But as a practical matter, just looking at the delegates, the numbers won8217;t really add up for her.8221;

Obama endorsed the idea Clinton needs wins in both states, which have a combined 334 delegates at stake, to prolong the Democratic race.

8220;If we do well in Texas and Ohio, I think the math is such where it8217;s going to be hard for her to win the nomination. And they8217;ll have to make a decision about how much longer they want to pursue it,8221; the Illinois senator said in an ABC interview shown on Good Morning America.

Republican front-runner John McCain, an Arizona senator, also can come close to clinching the nomination on Tuesday with expected wins over his last remaining major challenger, former Arkansas Gov. Mike Huckabee.

8216;Guardedly confident8217;

McCain told reporters in Phoenix he was 8220;guardedly confident8221; he could reach the 1,191 delegates needed to clinch the Republican nomination on Tuesday and move on to a general election campaign.

8220;I still respect Governor Huckabee8217;s right to remain in this race for as long as he feels necessary to do so,8221; he said.

Clinton8217;s advisers have worked overtime to roll back expectations and turn up pressure on Obama in Tuesday8217;s contests in the two big states and Vermont and Rhode Island. But they would not speculate on what Clinton would do in the case of a split decision.

8220;We are very optimistic about our chance of success in Ohio and Texas. If the outcome is different we can talk about it then,8221; said Clinton spokesman Howard Wolfson.

Like her husband, who nicknamed himself 8220;The Comeback Kid8221; for his improbable rise to the White House in 1992, Hillary Clinton has dodged predictions of doom before. In January, Obama appeared ready to deal her a knockout blow in New Hampshire after his big win in Iowa, but she defied polls and swept to victory.

A few weeks later, her landslide loss in South Carolina and a string of high-profile endorsements gave Obama momentum heading into Super Tuesday contests around the country, but she battled him to a draw and won most of the biggest prizes of the night in California, New York and New Jersey.

8220;This has been a roller coaster race, and every time people try to foreclose it the voters come back and say 8216;just wait a minute here, we want to have our say,'8221; Clinton strategist Mark Penn told reporters.

8220;Let8217;s see what the voters say, let8217;s take a look at what the situation looks like on Wednesday, and I think it will be pretty clear,8221; he said.

Clinton hunted for votes in Ohio and Texas on Monday. She began her day with a predawn visit to a Chrysler assembly plant in Toledo, Ohio, a city that has struggled with the losses of manufacturing jobs and poverty.

Clinton planned to buy cable time in the evening for a televised town hall meeting in Texas, while Obama planned a two-minute ad on evening newscasts in Ohio that it billed as his closing argument to voters.

Under Democratic rules allowing the losers in each state to win a proportional amount of delegates, Clinton will be unable to dramatically close the gap on Obama unless she scores big wins in Ohio and Texas that appear to be beyond her grasp.

Obama campaign manager David Plouffe released a memo questioning Clinton8217;s options if she does not make major strides in catching up to Obama in pledged delegates.

8220;While the Clintons gamely continue to try to move the goal posts, at some point there has to be a reckoning,8221; he said. 8220;What is their path to secure the nomination? No amount of spin can change the math.8221;