CHARLOTTE, N.C. — Campaigning his way toward the Democratic National Convention, President Obama slapped a ‘‘Romney doesn’t care’’ label on his rival’s health care views Sunday and said Republicans want to repeal new protections for millions without offering a plan of their own.
Vice President Joe Biden swiftly broadened the attack, accusing Republicans of seeking to undermine the decades-old federal program seniors rely on for health care. ‘‘We are for Medicare. They are for voucher care,’’ he said.
The president and vice president campaigned separately across three battleground states as delegates descended on Charlotte, the Democrats’ convention city, for two days of partying before their first official meeting Tuesday in the Time Warner Cable Arena. A 25-foot sand sculpture of Obama stood near the arena, made of mine sand from South Carolina.
Some 800 demonstrators marched through the streets near the convention hall, protesting what they call corporate greed as well as US drone strikes overseas, said to kill children as well as terrorists. Dozens of police officers walked along the parade route. One arrest was reported, for public intoxication.
The economy is the dominant issue of the campaign, and Biden’s itinerary, in particular, underscored the threat that a sluggish recovery and high, 8.3 percent unemployment pose to Democrats seeking another term in power.
He was in Pennsylvania and Wisconsin, states that have received little attention previously as the candidates, their parties, and outside allies concentrate on the areas of the country deemed most competitive. His presence suggested the race in both states was tightening.
Obama spoke on the University of Colorado campus in Boulder and made his now-familiar plea for students to register to vote. He benefited enormously from the support of younger voters four years ago and can ill-afford a fall-off in their support — or enthusiasm— in 2012.
Democrats regard passage of a sweeping health care law as a high point of achievement for Obama during his term. Yet the law has also unified Republicans who argue it amounts to a government takeover of the health care system and a budget-buster to boot.
Obama has lately been eager to answer his critics.
‘‘Governor Romney promised that on his first day in office he’s gonna sit right down, grab a pen, and repeal Obamacare,’’ the president said, referring to the law by the name Republicans first attached to it as an insult.
‘‘What that means is that right away he’d kick 7 million young people off their parents’ plan. He’d take hope away from tens of millions of Americans with preexisting conditions by repealing reform,’’ the president said.
‘‘You know, he calls it Obamacare. I like the name. I do care. . . . I don’t know exactly what the other side is proposing; I guess you could call it ‘Romney doesn’t care.’ But this law is here to stay.’’
Romney has provided only a few details of his plans to replace the law he wants to wipe off the books.
He proposes to guarantee a person who is ‘‘continuously covered’’ for a certain period be protected against losing insurance if he gets sick, leaves his job, and needs another policy.
Romney spent Sunday at his Wolfeboro, N.H., vacation home.