Opening a day of campaigning across battleground Virginia, Republican presidential nominee Mitt Romney offered himself here Thursday as a champion of business whose policies would usher in new jobs and rising incomes for America’s workers and entrepreneurs.

Addressing a crowd of about 2,800 on the factory floor of a window and door manufacturer in Roanoke, Romney pounced on a proposal President Obama reintroduced this week to consolidate multiple government agencies under a single secretary of business, charging that the president does not have the business know-how to jump-start the slow economy.

“I don’t think adding a new chair in his Cabinet will help add millions of jobs on Main Street,” Romney said. He added, “We don’t need a secretary of business to understand business. We need a president who understands business, and I do.”

Obama actually wants to eliminate two chairs from his Cabinet — the Small Business Administration head and the U.S. trade representative — and his proposed secretary of business would replace the secretary of commerce.

Romney’s campaign amplified the candidate’s new attack with a television advertisement released Thursday, as Romney’s support for business has emerged as a central theme of his closing argument to voters.

Romney repeated his mantra of “real change,” saying he would foster a more business-friendly environment in Washington by lowering corporate taxes and loosening regulations that he said inhibit economic growth.

“Today, we’re at the lowest level of new business start-ups in 30 years,” Romney said. “So I want to change this dynamic and make business recognize they have a friend in Washington, not a foe.”

Romney spent 25 years in the private sector — he founded and ran Bain Capital, a private equity firm — and his campaign is built around his management experience. But the Obama campaign cited Romney’s opposition to the federal bailout of U.S. auto manufacturers to suggest he had actually “turned his back” on businesses.

“The idea that Mitt Romney would help businesses grow as president doesn’t match his record or his policies,” Obama campaign spokeswoman Lis Smith said in a statement. “Mitt Romney can lurch from false attack to false attack in the final days of this campaign, but the American people understand President Obama is the only candidate in this race with a concrete plan to move our country forward, grow our economy and strengthen the middle class.”

But Romney argued that he, not Obama, has an agenda to turn around the economy. On the stump, a particular focus of his has been energy and his promise to develop more coal, nuclear and other domestic energy sources.

“We have this ace in the hole — this energy — and the president has been stalling on this for the last four years,” Romney said. “I won’t stall. We are going to unleash the power of our energy resources and get us back to being energy independent.”

Romney painted a dire portrait of America under a second Obama term, saying his reelection would lead to continued high unemployment and stagnant wage growth.

“We know something about the past, we’ve seen what his policies have produced – the only way to get this economy going is the kind of bold change I’ve described, real change from Day One,” Romney said. “That’ll get this economy going, create jobs, rising take-home pay. We’ll have a very different future when I get elected.”