(CBS) This story was written by CBSNews.com political editor Kevin Hechtkopf.
After a string of 11 straight losses, Sen. Hillary Clinton's presidential bid rests on the shoulders of voters in two large, vital states on Tuesday.
"This whole nominating process has come down to Texas and Ohio," no less an authority on the campaign than Bill Clinton said last week.
Both are states where Clinton has built-in advantages. Clinton has done well with Hispanic voters in states like California, where she won 67 percent of that vote, according to CBS News exit polls. In Texas four years ago, Hispanic voters made up a quarter of the Democratic primary vote. But a complex delegate allocation system that mixes a statewide primary with caucuses has complicated prospects for a clear win there.
It's one reason why Ohio may be Clinton's best opportunity for a big victory on Tuesday. But her campaign is facing a suddenly tough fight in a state with large numbers of the types of voters who have favored her in many contests this primary season - women, blue-collar workers and middle-class, lower-educated voters.
Polls taken just a few weeks ago in Ohio showed Clinton with a 15 to 20 point lead. The latest polls have shown that Clinton's lead has shrunk into single digits.
If Clinton is to be successful, she must avoid a repeat of the Wisconsin primary, where exit polls show that Sen. Barack Obama won with union households and with voters across all income and education levels.
Clinton was able to keep an advantage with white women, but her margin of victory with those voters was just 5 percent. Obama split the vote of all women and had the support of 67 percent of men in the primary.
Alexander Lamis, an associate professor of political science at Case Western Reserve University in Cleveland, said Clinton has reason for concern because Ohio and Wisconsin are actually very similar demographically.
"There was no reason to expect that [Ohio] was to be a firewall, or to now expect this to stop Obama's momentum," he said.
Lamis added that the Wisconsin results and narrowing polls in Ohio fit a pattern seen in several other states, in which Clinton had large early leads that shrunk to single digits or went away entirely.
"With all the things going for his campaign nationally, there's no reason to think those things won't play out in Ohio," Lamis said.
But the Clinton campaign is confident that Ohio will not turn out like Wisconsin.
"Ohio voters are independent," said Luiz Vizcaino, a spokesman for the campaign in Ohio. "Voters will decide on the candidate that makes change, and the change they want is experience."
The campaign is pulling out all the stops in the state, pouring resources into the state for ads, campaign events and organizational efforts. Vizcaino said the campaign will leave "no stone unturned" to reach out to voters.
The campaign's message in Ohio is the economy. Their television ads focus on plans for the middle class and "getting tough on unfair trade deals," including ones featuring Ohio Governor Ted Strickland and another with former Ohio senator and astronaut John Glenn. (Read about the Strickland ad in Horserace.)
At a town hall meeting this week in Lorain, outside of Cleveland, the candidate put the focus on key economic issues for Ohio voters - jobs, trade, health care and especially the home foreclosure crisis.
According to RealtyTrac Inc., Ohio ranks among top states in numbers of foreclosure filings. Last year, there were more than 150,000 filings, a jump of 88 percent from 2006. Four Ohio cities were ranked among the top twenty U.S. cities in foreclosure rates.
Clinton pushed her plan to freeze interest rates and offer help to homeowners. She repeatedly reached out to the crowd by saying she wanted to "help" Ohioans through tough economic times. "I can't help everybody, but I try," she said.
Mary Ann Kretovics, a first grade teacher from Lorain, said after the event she liked how Clinton talked about economic issues and said she thinks Clinton's chances are good in the primary. "I like that she's visible… she needs to keep doing that," she said.
The campaign touts endorsements from several members of the Democratic establishment in the state, including Strickland, Glenn, Lt. Governor Lee Fisher and Rep. Stephanie Tubbs-Jones. Obama's support includes state treasurer Richard Cordray and the mayors of Cincinnati and Cleveland.
The Obama campaign has also made the economy the central part of its pitch to Ohio voters - both on the trail and in radio and television ads stressing Obama's plans for jobs and the middle class.
While arguing that Obama is the "underdog" in Ohio due to Clinton's support from the political establishment, Obama's Ohio spokesperson Ben LaBolt said that the campaign's message is starting to resonate with voters like it has in other states.
Obama has outspent Clinton on ads in both Ohio and Texas and is getting additional help in the form of more ads from unions backing his candidacy. When everything is included, the difference in spending could be as much as two-to-one in Obama's favor.
Even if Obama doesn't win the state, his chief strategist David Axelrod sees the race as a fight for delegates.
"We’re trying to compete for every vote, every delegate in the four states that are on the ballot. And Ohio is obviously very very important," he said. "We don’t know where this is all going to end up next week. But we’re confident that we’ll get our share of delegates."
According to the latest CBS News tally, Obama has 1,373 delegates to Clinton's 1,265. On March 4, 370 are up for grabs, including 141 in Ohio. (Click here for the state-by-state CBS News delegate count.)
NAFTA, in particular, has been a flashpoint in the Ohio campaign. The free trade agreement with Canada and Mexico is widely unpopular here, especially with blue-collar workers who feel it has exacted a heavy price on manufacturing jobs in the state. According to the American Manufacturing Trade Action Coalition, Ohio has lost 236,000 manufacturing jobs since 2000.
Obama has used the issue as a wedge in Ohio, reminding voters that Bill Clinton helped push through the trade deal and contending that his opponent has supported it in the past. A mailer to Ohio residents from the Obama campaign containing claims Hillary Clinton had once praised NAFTA led to an especially strong response from the former first lady on Saturday.
"Shame on you, Barack Obama," she said, referring to both that mailing and another one she said distorted her health care plan.
Responding to the controversy on Tuesday in Lorain, Clinton said, "I got a little hot over the weekend in Cincinnati."
At the debate in Cleveland that night, Clinton tried to ensure that Obama's charges don't stick by pledging to withdraw from the deal if Canada and Mexico would not renegotiate key sections.
Obama agreed with that, but also reiterated the charge in the mailer that Clinton has "shifted opinions" since she started running for president.
Governor Strickland came to Clinton's defense after the debate.
"I think it's unfair for her to be held accountable," he said. "She had no vote on NAFTA."
Back in Lorain, Clinton's supporters said the key to her success is for the candidate to be visible in the coming days and stress her experience.
"I believe in her beliefs - what she wants to do in the country and the world," said Francis Manacci, 77, a Korean War veteran and retired foreman for U.S. Steel. "Obama is a nice person… but I give her the edge because of her experience."
If Clinton is to win in Ohio, she's going to need to the support of late-deciding voters. In Wisconsin, Obama convincingly won with voters who made their decision in the final month and final week before the vote.
Vickie Lewis, a 50-year-old transportation coordinator and single mom who said she's politically independent and an undecided voter, came to the rally because her daughter is a student at the high school where it was held.
While she won't commit to voting for Clinton, she said she "probably" will after hearing her appeal. She was impressed by Clinton's plans for health care and the economy and thinks she "has enough guts" to get things done.
"If she keeps walking the walk of what's she's talking about, that'd be awesome," Lewis said.