WAUKESHA, Wis. -- Democrats moved aggressively on Sunday to wrap Mitt Romney in the politically charged details of budget-cutting proposals championed by his new running mate, Representative Paul D. Ryan, as Mr. Romney sought to capitalize on conservative enthusiasm for his choice without having to defend every element of Mr. Ryan's positions.
In North Carolina and at an evening rally in Wisconsin, Mr. Romney praised his running mate for conservative vision and courage. But with Mr. Ryan's introduction to a national audience defined by his plan to reshape Medicare and slash spending for nearly all government programs outside the military -- policies that Democrats have spent years using to generate opposition to Republicans -- campaign aides pointedly noted that it was a Romney-Ryan ticket, not Ryan-Romney.
"I have my budget plan," Mr. Romney said on CBS's "60 Minutes." "And that's the budget plan we're going to run on."
The Republican team spent more time introducing each other to voters, smiling for pictures and sitting for their first joint television interview than they did delving into detailed policy proposals. Mr. Romney sought to get ahead of Democratic criticism by framing one of the more controversial elements of Mr. Ryan's approach as an effort "to make sure we can save Medicare."
But with some conservatives watching to see if Mr. Romney sticks by the ideas that have made Mr. Ryan a hero on the right, Democrats were intent on making Mr. Romney own every element of Mr. Ryan's record. They are not limiting their attacks to fiscal matters, but also highlighting Mr. Ryan's opposition to abortion rights and federal financing of contraception, issues the White House thinks could turn more women away from the Republican ticket.
President Obama, on a fund-raising visit to Chicago, welcomed Mr. Ryan to the race by describing him as the "ideological leader" of Republicans. His advisers worked to prepare a new advertising campaign to define the agenda advocated by Mr. Romney and Mr. Ryan as a threat to women, retirees and others. At the same time, they sought to pressure Mr. Romney to embrace or distance himself from Mr. Ryan's plans.
"I assume Governor Romney embraces his thinking, since he's invested so much in talking about Ryan's role as the intellectual leader of the Republican Party," David Axelrod, a senior adviser to the Obama campaign, said in an interview. "If he starts to distance himself from Ryan on positions that excite their base, I'm sure he'll have problems."
The Republican candidates accused the Obama campaign of having nothing positive to say and trying to change the subject from the administration's economic record. But in their "60 Minutes" interview, Mr. Romney and Mr. Ryan said that they had no intention of changing health coverage for seniors who are receiving Medicare benefits.
The debate over the future of Medicare has been reawakened by the selection of Mr. Ryan, who has advocated overhauling the program by creating a "premium support" system that would give future retirees the option of receiving a specified amount of money to buy private coverage, a change that independent analysts say could leave beneficiaries with higher costs, less coverage or both. Mr. Romney has indicated that he generally agrees with that approach.
"Governor Romney is at the top of the ticket," Kevin Madden, a senior Romney adviser, said Sunday, seeking to make clear that his decisions would drive the policy debate. "Governor Romney's vision for the country is something that Congressman Ryan supports."
The choice of Mr. Ryan was intended by Mr. Romney and his aides to change the trajectory of the race after months of attacks from the White House and pressure from conservatives to raise the stakes of the campaign by embracing a bolder agenda for reducing the size and the role of government.
As the pair appeared before enthusiastic crowds on their second day together, Mr. Romney presented Mr. Ryan as a bipartisan conciliator in Washington and a man with ideas who works with Democrats on problems. It is at odds with how Democrats in Congress describe Mr. Ryan, whom they like personally but whose views they characterize as extreme.
But in the interview on "60 Minutes," Mr. Ryan, 42, introduced himself as a patriot committed to turning around the country's fiscal challenges. "We've dedicated much of our lives to saving this country," Mr. Ryan said when asked about bursting onto the national stage.
When he arrived at a homecoming rally here on Sunday evening, Mr. Ryan wiped away tears as he took the stage and looked out upon a sea of familiar faces in the crowd. "Hi, Mom," he said, choking up as he pointed to friends and neighbors who hailed him as a proud son of Wisconsin.
Gov. Scott Walker of Wisconsin, a Republican who survived a divisive recall election in June in a fight over collective bargaining that has made him into something of a conservative icon, said Sunday that members of his party should not be worried if Mr. Romney does not fully embrace every aspect of Mr. Ryan's budget, which has become a centerpiece of the party's fiscal agenda.
"Mitt Romney will have his own plan, but he values someone who has the courage to take on the tough issues," Mr. Walker said in an interview. "With Paul on the ticket, you have the credibility of knowing that Paul Ryan is not going to be a wallflower. He is going to be an active part of a Romney administration."
The debate over Medicare was an undercurrent at the Republican rallies on Sunday. It remains an open question whether attitudes are changing about the tough-medicine approach advocated by Mr. Ryan for a program that is on a trajectory of ultimate insolvency. Several older voters said they supported Mr. Ryan's plans to overhaul the program and would be disheartened if Mr. Romney backed away from them.
"I'd be disappointed," said Chuck Bino, 71, who added that Mr. Ryan's bold thinking on such issues is what convinced him Mr. Romney was not the "middle-of-the-road candidate" he feared.
While Medicare is a renewed focal point of the campaign, Democrats are digging into the Republican budget to highlight the implications for people across demographic groups, including proposed cuts to veterans' programs, student loans and regional programs. For the next three months, a debate that has largely taken place in Washington will be elevated to a national audience.
The addition of Mr. Ryan to the ticket has not redirected the focus of the campaign, Democratic strategists said, since Mr. Romney had already endorsed most of the provisions of the Republican budget. But they say it has intensified the budget debate and shined more light on all of the provisions of Mr. Ryan's plan.
Democrats on Sunday also seized on how Mr. Romney asked his prospective running mates to be more forthcoming in their tax information than the two years of returns that he has agreed to release. Mr. Ryan released several years of tax information to the campaign during his vetting, but like Mr. Romney he will publicly release only two years of returns.
But the thunderous reception the Republican ticket received at an evening rally in Wisconsin, with thousands of people filling an outdoor park in here in Waukesha, west of Milwaukee, capped a weekend where Mr. Romney saw the biggest and most enthusiastic crowds of his candidacy. After two days of joint campaigning, the men will go their own ways, with Mr. Ryan heading to Iowa and Mr. Romney traveling to Florida.
As Republicans head to their convention at the end of the month, a theme has emerged that advisers to Mr. Romney said underscored how the script had been flipped. A vote for Mr. Obama is an endorsement of the status quo, Republicans will argue, while a vote for Mr. Romney is a call for change.
Jodi Kantor contributed reporting from Chicago.
This article originally appeared in The New York Times.