OHIO: Barack Obama intensified his bid to end Hillary Clinton’s White House quest in Tuesday’s momentous nominating contests in Texas and Ohio, as both rivals geared up massive voter turnout drives.

Clinton meanwhile, in a wistful moment, said she would examine her options when the results were in, after several top Obama backers upped pressure on her to concede the Democratic nomination if she fails to score big victories.

“I intend to do as well as I can on Tuesday, we will see what happens after that,” the former first lady said in a late-night press conference on her campaign plane, pointedly declining to predict victory.

Clinton was up before dawn on Monday, on a gruelling last day of campaigning, greeting workers as they clocked on in at a Chrysler car plant in Toledo, Ohio, an epicenter of her blue-collar voting base.

“Hi, I need your help tomorrow,” she said, as workers filed past her position alongside a make-shift donut stand, outside the plant.

Both campaigns were on Monday cranking up huge turnout operations in the two states, sending thousands of volunteers to drive supporters to the polls, amid concern about bad winter weather forecast for some parts of midwestern Ohio.

After a rally in Toledo, Clinton was due to head for Texas, where she was holding a televised townhall meeting, before shuttling back to Ohio on Tuesday.

Obama was also heading to Texas, and planed to stay in the Lone Star state to hear returns roll in Tuesday night.

The Illinois Senator, who would be the first African-American president, hit back after Clinton said on Saturday his entire campaign was based on just one anti-war speech in 2002, as part of a withering critique of his national security credentials.

“When it came time to make the most important foreign policy decision of our generation — the decision to invade Iraq — Senator Clinton got it wrong,” Obama argued in Westerville, Ohio on Sunday.

“To this day, she won’t even admit that her vote was a mistake or even that it was a vote for war,” he said referring to the New York senator’s 2002 decision to authorise force in Iraq.

Clinton, desperate to halt Obama’s winning streak at its current 11 straight nominating contests, meanwhile raised fresh doubts about whether he was ready to serve in the Oval Office.

“You never know what crisis is going to happen,” Clinton said in Austintown. “I know that I will be able to defend our country.” Former presidential candidate Bill Richardson, yet to endorse one of his former rivals, earlier expressed concern that a prolonged clash between the two Democratic titans could damage the party as it gears up to challenge presumptive Republican nominee John McCain.

“D Day is Tuesday. We have to have a positive campaign after Tuesday,” he told CBS.

“Whoever has the most delegates after Tuesday, a clear lead, should be in my judgment the nominee.” Top Obama allies Senator Richard Durbin and Senator John Kerry argued meanwhile that Clinton needed big wins to catch her rival’s tally of nominating delegates and should consider her options.

The latest count of nominating delegates, awarded after each state contest, by website RealClearPolitics shows Obama leading by 1,389 to Clinton’s 1,279, with the freshman senator pulling into the lead after 11 nominating wins in a row.

A total of 2,025 delegates is needed for victory at the Democrats’ convention.

Tuesday’s votes look unlikely to change that picture much, given that Democratic primaries award delegates on a proportional basis.

A Cleveland Plain Dealer poll found Senator Clinton slightly ahead in the economically struggling state, by 47-43 per cent.

Obama led in Texas by 46-45 per cent, according to polling by McClatchy Newspapers, MSNBC television and the Fort Worth Star-Telegram.

Clinton, 60, and Obama, 46, are battling for the right to carry the Democratic banner in November against likely Republican nominee John McCain.

He enjoyed a down weekend at his home in Arizona, but was due to hit the campaign trail in Texas on Monday, as he tries to finally end the pesky and academic challenge of Republican challenger Mike Huckabee.—AFP