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Paul Ryan got his first full run as GOP vice presidential candidate Sunday, attracting overflow crowds in NASCAR country and finishing the day before a hometown crowd in Wisconsin. He used a string of appearances at Mitt Romney’s side to help the Republican candidate refocus the race on fiscal issues and energize the base.

“We can change this thing and get it back on track,” said the Wisconsin GOP congressman at the NASCAR Technical Institute in Mooresville, N.C., the first stop in a long Sunday of campaigning.

Romney did much of the talking during the two-state tour -- one day after he announced the 42-year-old Ryan as his running mate and the two embarked from Norfolk, Va., on a campaign bus trip.

Still, Ryan at times showed his readiness to be the traditional vice presidential attack dog.

America is "a nation facing debt, doubt and despair," he said. "Regrettably, President Obama has become part of the problem.”

A clearly energized Romney spent much of the time praising Ryan.

“His career ambition was not to go to Washington,” he said. “That is not what he wanted to do. But he became concerned about what was happening in this country. … So he put aside the plans he had for his career and said I’m going to go and serve.”

Standing in front of a NASCAR vehicle painted with the words “Romney Believes in America,” Ryan reminded the overflow crowd that the state unemployment rate is at 9.4 percent and that he and Romney offer them a choice in deciding the future of the economy.

"You could not have a better contrast than this," Ryan said, as Romney looked on, smiling.

The team later travelled to High Point, N.C., where the seven-term congressmen reworked his often-repeated phrase about how the November election will be “our generation’s test.”

“And when a country is facing a test like this is when the country so needs leadership,” he continued.

About 1,500 people waited -- some more than five hours -- in a cavernous warehouse with struggling air conditioning, while 2,000 packed into a cleared-out furniture showroom where the air was sticky and heavy. Thousands more stood behind barriers erected on the street outside -- Romney and Ryan stopped on their way in to give high fives to a few in the cheering crowd.

"We love you," Romney cried.

Ryan got noticeable teary on the final stop in the day – the Waukesha County Expo Center in Wisconsin.

Spotting local reporters before the event he told them: "It feels great. It's nice to be home. I've been flying into this runway a long time. It's just nice to come home."

Ryan’s next stop is the Iowa State Fair while Romney continues his bus tour into Florida, then Ohio on Tuesday. The team is not expected to meet again until the Republican National Convention.

“This has more to do with expanding our bandwith,” Romney aide Kevin Madden said to reporters.

The Romney-Ryan chemistry became clear well before Ryan joined the ticket and was on full display Sunday.

"I am so happy. I am so happy to have my teammate now," Romney said before departing from North Carolina with Ryan.

He was so happy, in fact, that when the crowd inside the venue in Moorseville, about 50 miles outside Charlotte, broke into Romney's speech to chant, "USA, USA," Romney joined in -- and pumped his fist in the air. He was right in step with Ryan, who was standing on stage with him doing the same thing.

Romney called Sunday "Day 2 on our comeback tour."

By aligning with Ryan, Romney has created a Republican ticket with economic overtones that will appeal deeply to the conservative Republican base which favors small government and low taxes.

But the move also hands the Democrats a campaign hammer, a tool that will allow them to pound the Republican ticket for planning to gut Medicare, the government health insurance program for Americans 65 and older, and Medicaid, the program that provides health care to America's growing number of poor people.

The Associated Press contributed to this report.