PHILADELPHIA, Pennsylvania (CNN) -- Sen. Barack Obama, trying for an upset in Pennsylvania's pivotal April 22 primary, is hoping the Teamsters Union can help him reel in the state's huge blue-collar vote.

Sen. Barack Obama speaks at a rally in Harrisburg, Pennsylvania, in March.

Teamsters president Jim Hoffa, leading a convoy across Pennsylvania, told CNN that he believes the Illinois senator "can change this country."

Obama, who hasn't been doing well with blue-collar workers, took his own tour across Pennsylvania.

"I met folks in factories and on farms, in bars and bowling alleys," Obama recently said.

Hoffa said voters desperately want change.

"There's a despair out there that we can't change things, we've been beaten down," Hoffa said.

On Wednesday, the Teamsters convoy made its way to Reading, Pennsylvania, where the York Peppermint Patty factory is shutting down, moving more than 250 jobs to Mexico.

The target of the workers' anger, according to Hoffa, is NAFTA.

"People remember Clinton and NAFTA, and I think when we talk about changing NAFTA, I think that Barack Obama has more credibility," he said.

Obama is running as a Washington outsider, and he subtly reminds voters that he's not part of that system.

"For over two decades, what we heard from the Bush administration is ... you're on your own," Obama has said.

But the two decades he refers to would include the Clinton years in The White House.

Obama is counting on his outsider appeal, more than his lifestyle, to break Clinton's lock on blue-collar voters in Pennsylvania.

He reminds workers that when it comes to enjoying the gains of economic growth, they're outsiders, too. E-mail to a friend

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