(Charlotte, North Carolina) Democratic vice presidential candidate Joe Biden said Thursday that Republican rival John McCain is “getting a little loose” at a time when the nation needs a steady hand.

Campaigning in NASCAR country, Biden employed car racing terminology for bumping to describe the contentious final days of the campaign. He told supporters in Charlotte that he’s worried about how the Republicans have been acting as the two campaigns have been “trading a little paint” recently.

“What worries me most is the McCain campaign seems to have gotten a little loose,” Biden said. “John’s getting a little loose. He doesn’t have much of a steady hand these days. Now’s the time we most need a steady hand.”

The Delaware senator told the crowd the nation needs to unite to address the challenges ahead. He called Republican robocalls “scurrilous” and said ads portraying Obama as an extremist hurt the American people.

“It is corrosive to American society,” Biden said. “It’s awfully hard to build anything with that kind of corrosion.”

Although warning of the dangers of political divisions, Biden took aim at McCain. Deriding McCain’s effort to dissociate himself from President Bush, Biden accused the Arizona senator of “quacking like George W. Bush.”

And after botching McCain’s name, Biden joked he no longer knew his longtime Senate colleague.

“John McClain. John McClain. Excuse me, John McCain. John McCain - I don’t recognize him anymore,” Biden said to laughter from several hundred supporters in attendance.

Republican National Committee spokesman Alex Conant said Biden was being loose with his rhetorical flourishes and offered a different NASCAR analogy: “If Obama wins, he will raise taxes and our economy will go from a yellow to red flag.”

Biden’s criticisms appeared to refer to a mailer distributed by North Carolina’s Republican Party last week. The ad tries to link Obama to 1960s radical William Ayers with pictures of Ayers, including his mug shot, and a description of Ayers’ violent anti-Vietnam war activities from decades ago. The mailer declares the two are friends and says Obama is “not who you think he is.”

Obama has condemned Ayers’ radical activities, which occurred when Obama was a child. He met Ayers a quarter century later when Ayers was an education professor at the University of Illinois and a Chicago neighbor. They worked on the boards of two nonprofit charitable groups from the mid-1990s to 2002, and Ayers held a meet-the-candidate event for Obama when he first ran for the Illinois senate, but the two are not close.

Biden was on a bus tour through college campuses in North Carolina’s more liberal corridors - the fast-growing urban areas that have pushed the state toward the Democrats for the first time in decades. He also planned stops in Winston-Salem and Raleigh.

McCain’s campaign announced he would return to the state Tuesday.