Hillary Clinton is striving to stem rival Barack Obama's momentum with a strong showing in Wisconsin's primary, even as she loses ground in Texas.
Mr Obama is expected to win the Democratic caucus in Hawaii, the Pacific islands state where he was born. If he sweeps Wisconsin as well, he could lock in his tenth straight win in the two weeks since Super Tuesday's contests failed to give either candidate a decisive lead.
A Wisconsin win for Mrs Clinton could give the New York senator's faltering campaign a much-needed boost ahead of a major showdown on 4 March in Ohio and Texas, which offer a large number of delegates.
She had been ahead by double digits in both states, but a poll released yesterday by CNN showed the race in Texas has narrowed to just two points, well within the margin of error.
Even decisive victories in all three states would not be enough to sew up the 2,025 needed to win the Democratic nomination.
Mrs Clinton is currently trailing Mr Obama 1,212 to 1,262 delegates.
With polls showing the Wisconsin race too close to call, both campaigns fired off combative television advertisements, braved blizzards to shore up support across the midwestern state, and struggled to control expectations.
With blue-collar workers considered a key voting bloc in Wisconsin, Mrs Clinton unveiled a 13-page 'economic blueprint' to create new jobs, end the housing crisis and revive the manufacturing sector.
The rival campaigns also exchanged fire yesterday, accusing each other of borrowing lines for their speeches. Hillary Clinton laid into Mr Obama again over his soaring oratorical style.
Mr Obama insisted that the country needs an inspirational leader to overcome a host of problems.
While the Democrats slugged it out, Republican front-runner John McCain has won the endorsement of former president George H W Bush.
This new backer could help the maverick senator court conservatives suspicious of where his loyalties lie.
Mr McCain picked up the elder Mr Bush's endorsement, but the current President George W Bush has yet to endorse anyone. However, he said he would help Mr McCain if he won the nomination.
Mr McCain is almost assured to win the Republican nod, but former Arkansas governor Mike Huckabee has refused to step aside despite trailing by hundreds of delegates.
He continued to reach out to the party's conservative base as he campaigned in Wisconsin.
