HILLSBOROUGH -- During a rally Wednesday, former President Bill Clinton emphasized the importance of North Carolina's May 6 primary in deciding the next Democratic nominee for president.

"This is the biggest state still to vote," he told several hundred people gathered on a ball field. "Your voice will resound across America."

Clinton boasted of his wife's win in Pennsylvania on Tuesday. He said that Sen. Barack Obama outspent her 3-1 on TV ads and yet she still carried the state by a 10-point margin. Obama, however, remains ahead in the delegate count.

Speaking in the home county of John and Elizabeth Edwards, Clinton noted that Mrs. Edwards has said she favors Sen. Hillary Clinton's health-care plan over Obama's.

"She said Hillary's health-care plan was better, and as you all know, she knows something about that issue," he said.

He also talked about his wife's proposals to reach energy independence and promote development of affordable hybrid cars.

"If our country can beat the world to the moon," he said, "we ought to be able to beat the world to clean coal and a car battery."

The Clintons' focus on cutting Americans' energy costs resonated with the crowd Wednesday, especially President Clinton's pitch for cars that can go 100 miles on a gallon, of which he said there are 50 in the United States.

"I'd like to have a car that'd go 100 miles per gallon," said 45-year-old Julie Terrell of Mebane. "Are they going to give us the money so we can afford the cars that go 100 miles per gallon? That would be the hard part."

Polls show Obama with a large lead among N.C. Democratic voters, but Clinton's state field director Mike Trujillo said the same was true in California and Texas, primaries that Clinton eventually won.

The audience was packed with Clinton supporters Wednesday, but some Obama backers, undecided voters and Republicans were also in the mix.

Though Mr. Clinton mentioned Chapel Hill Town Council member Sally Greene, Orange County Commissioner Mike Nelson and Carrboro Alderman Dan Coleman, no local politician appeared with him on a makeshift stage on the back of a pickup truck. The mayors of Chapel Hill, Carrboro and Hillsborough held a fundraiser for Obama on Thursday night.

Susan Burgess, Charlotte's mayor pro tem, introduced Clinton Wednesday, calling on Obama to debate Sen. Clinton in North Carolina, something the Illinois senator has so far declined.

"During [Clinton's] administration, America experienced the greatest period of shared prosperity and peace in the history of our great nation," Burgess said. "Our current president and the Congress have reversed every one of those accomplishments, and that's why we need another Clinton administration."

The scheduled start of the event was 1:45 p.m., but the crowd began to chant "We want Bill" long before he made his appearance. They waited more than an hour, through T-shirt giveaways and a raffle to meet the former president. He made his fifth swing through the state Wednesday on behalf of his wife's campaign.

"It's a great opportunity to come here [and see] a former president who I have a lot of respect for," said Elisabeth Smith, 38, of Carrboro.

Smith said she's undecided. Her respect for Bill isn't enough to guarantee a vote for Hillary. But Paul Brodish, 44, of Carrboro, thinks they're a great team.

"You get two-for-one if you vote for Hillary," Brodish said. "He's been there, done that, and he did a good job. He'd be her first adviser. You get two times the brain power. You can't go wrong."

"I like her because you can knock her down, and she comes right back up," said 63-year-old Jo Ann Snead of Hillsborough.

"But she comes up spitting, and [Obama] comes up smiling," replied her friend, Rollin Russell, 71, also of Hillsborough. Russell, a retired United Church of Christ pastor, has known Obama's former pastor, the Rev. Jeremiah Wright, for 20 years. Obama impressed Russell when the senator spoke at a national church gathering in 2005.

"He's a new era in politics, and we need it bad," Russell said. "I'm a Barack supporter, but I love Bill, and I love Hillary, too. I think he was a great president if he could have kept his pants zipped. Lovable jerk -- that's what Americans seem to elect -- him and George Bush. But at least Clinton had some intelligence and commitment to help people, not his rich buddies."

Kate Jackson, a registered Republican from Chapel Hill, said she supports Clinton because she thinks the New York senator is best-prepared to fix problems in the economy and foreign policy. She said she appreciated Trujillo's comments that "boys" in both parties have been telling Clinton to "sit down, shut up and be quiet."

Jackson said, "I think that people are intimidated by her because she's a woman."