WASHINGTON -- In choosing Rep. Paul Ryan of Wisconsin as his running mate Saturday, Republican presidential candidate Mitt Romney tapped someone who has the power to energize the Republican Party’s base – and the Democratic Party’s, too.

The presence on the GOP ticket of Ryan, the House of Representatives Budget Committee chairman, whose plan to cut taxes, reduce spending and revamp Medicare is regarded as a Republican Party road map, ensures that two very different visions of the role of the federal government in America will be front and center in this fall’s presidential campaign.

Ryan, 42, wasted no time Saturday in framing the Republican case against President Barack Obama.

“I hear some people say that this is ‘the new normal,’ ” Ryan said in Norfolk, Va., with the battleship USS Wisconsin as a backdrop. “High unemployment, declining incomes and crushing debt is not a new normal. It’s the result of misguided policies.”

He and Romney then began a tour that took them through Virginia on Saturday and had them scheduled to visit North Carolina, Florida and Ohio next, all states Obama carried in 2008 and that Romney must win if he is to unseat the president.

The new Republican ticket was well received in Virginia. Charlie DeGraw, 63, the owner of Charlie D’s Next Day Tees, drove to a Romney-Ryan rally in Manassas, Va., after watching the Norfolk event on Fox News. He stopped by his shop and printed out a neon green Romney-Ryan 2012 T-shirt for the occasion.

“I’m very excited,” DeGraw said. “He solidifies my support for Romney.”

Barry Gill, 29, who attended the Manassas event with his wife and three children, said the Ryan pick surprised him. He preferred Rubio as a running mate and thinks Ryan could be more effective remaining in the House.

“I’m a big fan of Ryan’s budget,’ he said. “It’s a double-edged sword.”

The Obama team welcomed Ryan, a seven-term congressman, to the campaign trail with a blistering critique.

“In naming Congressman Paul Ryan, Mitt Romney has chosen a leader of the House Republicans who shares his commitment to the flawed theory that new budget-busting tax cuts for the wealthy, while placing greater burdens on the middle class and seniors, will somehow deliver a stronger economy,” Obama campaign manager Jim Messina said.

Romney’s announcement ended a four-month search that was shrouded in speculation, secrecy and questions about whether he’d play it safe and select a steady but unspectacular running mate, such as Sen. Rob Portman, R-Ohio, or former Minnesota Gov. Tim Pawlenty, or make a bold statement by choosing someone such as Florida’s Sen. Marco Rubio, who’s Hispanic, or a woman such as Sen. Kelly Ayotte, R-N.H.

Romney seemed so excited about his choice Saturday that he inadvertently introduced Ryan as the next president of the United States.

“Every now and then I’m known to make a mistake,” Romney said, interrupting the start of Ryan’s acceptance speech. “I did not make a mistake with this guy.”

In the end, Romney managed to pick someone who was both a safe and bold choice, several political experts said.

“It’s safe in that Paul Ryan fits Mitt Romney’s comfort zone. He’s an extension of the (Romney) family; he’s as young as one of Romney’s sons,” said Tim Walch, the editor of a book of essays on the vice presidency, “At the President’s Side: The Vice Presidency in the Twentieth Century.” “And he’s the type of person Romney worked with at Bain Capital: whip-smart, kind of a wonk who can break down policy to find solutions. It’s bold because it really energizes the right wing of the Republican Party at the time Romney needs a boost the most.”