Speaking to United Auto Workers Local 12 in Toledo, Biden said he and President Obama are looking out for the middle class, while Republicans are only interested in helping the very wealthy.
"I'm back, you're back, and the industry is back," Biden said after quieting cheers of "four more years" from the blue-collar crowd.
"The president and I made a bet, a simple bet. We bet on you. We bet on American ingenuity. We bet on you and we won. Chrysler, fastest growing car company in America, General Motors has seen the largest profits in its history."
Biden said the administration measures economic success by whether the middle class is growing, while Republicans are concerned with the privileged few.
"Mitt Romney, Rick Santorum, and Newt Gingrich -- these guys have a fundamentally different economic philosophy than we do. Our philosophy, ours is one that values the workers in the success of a business. It values the middle class and the success of our economy. … We're about promoting the private sector, they're about protecting the privileged sector. We are for a fair shot and a fair shake. They're about no rules, no risks, and no accountability."
Biden noted Romney, a former Massachusetts governor and the front-runner for the GOP presidential nomination, had penned an op-ed titled "Let Detroit Go Bankrupt" at the onset of the financial crisis.
But Biden said Obama "wasn't going to give up on a million jobs and on the iconic industry America invented."
He also said Obama's "historic fuel economy efficiency standards … nearly doubled the efficiency of cars, saving the American families $1.7 trillion at the pump, helping free us from foreign oil dependence. And they were against that too."
"I want to tell you what's real bankruptcy, the economic theories of Gingrich, Santorum, and Romney -- they are bankrupt. If you give any one of these guys the keys to the White House, they will bankrupt the middle class again."
Biden said the general election will be "a choice between a system that's rigged and a system that's fair," adding the administration advocates "a system that trusts the workers on the line instead of listening to the folks up in the suites."
After leaving the plant, Biden made a stop at Glenwood Elementary school in Rossford and posed for pictures with dozens of children.
"You guys are all so nice to say hi to me. I will tell President Obama you said hi," he told the students.