FALCON HEIGHTS — U.S. Senate candidates Amy Klobuchar and Kurt Bills met for the first wide-ranging debate of the campaign Thursday, a lively Minnesota State Fair exchange that showcased deep policy differences between the candidates and no reluctance from either to fling tough rhetoric.

The debate, aired live on Minnesota Public Radio, focused largely on the federal budget, taxes, spending and jobs. But it also touched on foreign policy and veterans issues, global warming and energy, agriculture and trade policy, and social issues.

The candidates displayed wide differences on fiscal policy. While both acknowledged the need to address the massive federal debt and deficit, they diverged strongly on how best to do it. Klobuchar, the Democratic incumbent, called for spending cuts mixed with allowing the expiration of President George W. Bush-era tax cuts on yearly income above $250,000.

She said that alone would raise an additional $700 billion a year.

“That’s a big chunk of change. It must be a balanced approach,” Klobuchar said.

Bills, a Republican state representative and high school economics teacher from Rosemount, called instead for implementation of a 1980 flat tax proposal floated by a pair of think-tank economists. He said it would treat all taxpayers the same, make filing taxes easier and zero out tax loopholes.

“You want to get rid of loopholes for the wealthy, I’m your guy because I’ll get rid of all of them,” Bills said.

The debate was notable for its sharp tone. Klobuchar is widely perceived as a heavy favorite to win re-election, a dynamic that even Bills acknowledged in a radio interview last week when he said Klobuchar would win if the election were held now. But that didn’t stop the incumbent from acting like a challenger, ridiculing Bills for legislation he sponsored at Minnesota’s Capitol to make gold and silver coins legal tender.

“I don’t believe that’s where Minnesota is headed,” Klobuchar said.

That set off Bills, whose voice rose as he returned to an earlier comment from Klobuchar that her main priority was helping the middle class.

“If you actually cared about the middle class, you’re looking at them,” Bills said. “Trust me, I’m well within the middle class. I’d be proud to be the poorest member of the U.S. Senate. Maybe you need to start sending people like me to the U.S. Senate.”

The tone rarely abated, whipped up by a live audience heavily stacked with supporters of both candidates who clapped, cheered and hooted after nearly every response. Bills painted Klobuchar as a creature of Washington and said Congress needs new faces to take on the country’s biggest challenges.

“This election is not Republican versus Democrat anymore,” Bills said. “It’s America versus Washington, D.C.”