In the end, both men convinced him they would work to stem the flow of jobs overseas. But Knickerbocker is leaning toward Kerry, who he thinks could more easily oust President Bush. The issue that disappoints Knickerbocker most about the president? Jobs.
"We just can't have four more years of an attack on labor," the 59-year-old construction worker said at a rally in the Cleveland suburbs, where he listened to Kerry speak mostly about jobs.
In Ohio, which is bleeding manufacturing jobs, and in other industrial states holding primaries Tuesday, the loss of jobs has emerged as the burning issue for many Democratic voters and the focus of candidates' speeches.
No wonder. Across the 10 states that vote Tuesday, 900,000 jobs have evaporated since 2001, more than a third of the national total. And the three states that have lost the most jobs -- Ohio, New York and California -- all hold primaries Tuesday.
The issue is sure to remain important through the general election as well -- perhaps the signature issue, if Democrats have their way. It could pose a stiff test for Bush, who has been stressing in speeches how committed he is to creating jobs.
As Democrats like to point out, nearly 3 million jobs have vanished in Bush's first three years in office. That makes his record worse than any president's since Herbert Hoover.
The president's defense is that he inherited a recession and that two wars have weighed down the economy. But his message might not be resonating. In a Newsweek poll released last week, 55 percent of voters said they disapproved of Bush's handling of "jobs and foreign competition." Only 33 percent said they approved.
History suggests that the president can hardly afford to ignore Ohio and the plight of its manufacturing workers. No Republican has ever won a presidential election without carrying this state, which Bush won by just 3 percentage points over Al Gore in 2000. Every sign is that the state will be a key battleground again this time.
Rick Farmer, a campaign specialist at the University of Akron's Ray C. Bliss Institute of Applied Politics, predicted that jobs will be the "salient issue" on the minds of swing voters in Ohio as they weigh their choice in November.
"You have union voters here who may also be conservative on social issues and want to protect their gun rights -- but who above all are concerned about their job," Farmer said. "Bush will come here and will aggressively defend his record. But when people don't have a job and are worried about their job, talking about how the economy is in pretty good shape will be a difficult sell for him."
In an economy that is by most measures in healthy recovery, jobs have been created more slowly than economists had predicted. Economists say that manufacturers have seen greater productivity from their workers, thanks to new technology. That means employers are not rushing to hire again even as the economy gains strength. Open trade deals, too, have encouraged U.S. companies to move abroad and take advantage of cheap labor.
Uneasiness about the job climate has emboldened Bush's rivals. Nobody more than Edwards has tried to capitalize on the anxiety among workers.
The North Carolina senator, visiting union halls and factories in Ohio and elsewhere, has delivered a message that he -- not front-runner Kerry -- cares most about boosting ordinary workers. He underscores this claim by playing up his past as the son of a millworker.
Edwards has tried to tap into anger over the 1993 North American Free Trade Agreement, which Kerry voted for and which critics say has shipped jobs overseas. Edwards was not a senator at the time but says he would have opposed the deal.
Edwards' anti-NAFTA attacks helped attract wavering Democratic and independent voters in the industrial state of Wisconsin. He finished close enough behind Kerry there to sustain his campaign. Like Wisconsin, Ohio allows independents to vote in the Democratic primary.
In Ohio, Edwards appears to be taking a page from the playbook of Gary Hart. In 1984, Hart also faced steep odds to battle back and win the Democratic presidential nomination. Hart brought his sputtering campaign to Ohio and made a last-ditch appeal to voters in this economically depressed state.
He accused front-runner Walter F. Mondale of ignoring steelworkers and other manufacturers while he was Jimmy Carter's vice president, helping put 114,000 Ohioans out of work. Riding this message, Hart surged in the polls late and won a stunning upset. It breathed new life into a campaign that lived on, at least for a while.
In substance, Edwards' call to renegotiate NAFTA and ensure it does not harm American workers by allowing companies to move operations overseas differs little from Kerry's position. But Edwards has been playing up the contrast between himself, the son of a millworker, and Kerry, a product of New England wealth, suggesting that his promises to help ordinary Americans are more sincere.
Bush recently got a taste of the potency of the attacks on jobs to come. Talking with reporters, his chief economic adviser, Gregory Mankiw, made an offhand suggestion that sending some jobs abroad can help the economy -- a notion most economists agree with. Yet the comment drew attack from Democrats. Bush was forced to respond with assurances that he will work to protect jobs from leaving the country.
Gary Hufbauer, a fellow at the Institute for International Economics, pointed out that any president is vulnerable to attacks for backing free trade. A world leader who speaks out against an existing trade deal could trigger unpredictable diplomatic consequences.
"The president can't just be a politician on the matter -- he has to think about the economic realities, but then he'll get hit from the other side," Hufbauer said. "The anti-NAFTA, anti-outsourcing, anti-trade message lets you, in a few words, get an emotive response from a lot of people who blame their problems on free trade."
The issue of jobs and trade probably represents Edwards' last hope to re-ignite his campaign and keep him competitive beyond Super Tuesday.
Chris Chafe, political director for the Union of Needletrades, Industrial and Textile Employees, which has backed Edwards, said his organization helped turn out voters for the senator in Wisconsin and has been campaigning hard for him in Ohio. Chafe said the textile industry has been devastated by NAFTA, having lost 850,000 jobs -- or 58 percent of the entire industry -- since the deal took effect.
Chafe said Kerry has long favored free trade and has been talking about protecting jobs "mostly because he is a good politician and has been listening to Americans." By contrast, he said, Edwards "has lived many of the problems." Still, Chafe said his union is preparing for the possibility of a Kerry-Bush race and would mobilize aggressively for Kerry because it views Bush as a threat to jobs.
Aides to Kerry say his national endorsement from the AFL-CIO has served as "Teflon" against Edwards' attacks on his jobs record. But at a Kerry rally near Cleveland last week, Tim Buxton, a staff representative for the United Steelworkers of America in Ohio, sounded lukewarm in supporting him.
"He is decent on the issues and has a respectable record on labor -- he'll do fine," Buxton said. "But that NAFTA message Edwards is saying is not the wrong message. And Kerry, if he is to carry the day, won't be able to ignore it."
Gary Burtless, a labor economist at the Brookings Institution, said he marvels at how much politicians talk about NAFTA and about how free trade threatens American jobs. In reality, he said, the vast majority of U.S. job losses have been because of the recession and improved productivity.
"The politics are obvious," Burtless said. "If they can say some change in the world is because of evil foreigners and their handlers in our country, they'll do it. The truth is our economy had a recession and the recovery is far from complete."