Democratic vice presidential candidate John Edwards (search) alternated on Thursday between projecting the sunny optimism that won him praise during the primaries and assuming the attack-dog mantle usually associated with the No. 2 on the ticket.

It wasn't always smooth, as Edwards sometimes careened between the two approaches as he greeted voters in a middle-class neighborhood of New Orleans on his second day of solo campaigning.

"People want to feel hopeful, want to feel that things will be better," the first-term North Carolina senator and former trial lawyer said as he chatted with Donald and Charmaine Carrere on the front porch of their one-story, green clapboard home.

The couple told him they were having a hard time making ends meet: one son recently graduated from college, another just started. "It seems like every time I get a raise, it's sucked up by something else — tuition, gas, taxes," Donald Carrere said.

Edwards empathized with the family and its problems, and said that was one reason why he and presidential candidate John Kerry (search) were seeking the views of ordinary Americans. "You have to do this to hear what's going on," he said.

Then Edwards segued into a criticism of President Bush's Iraq policy.

"Going it alone is just a mistake," Edwards said of the administration's decision to invade Iraq without broad international support. "Are we not safer in a world where we're looked up to? It's not complicated."

A day earlier, Edwards took the lead for Democrats in challenging President Bush to take responsibility for mistakes in Iraq as British Prime Minister Tony Blair (search) had done.

At a town hall meeting in another section of New Orleans, Edwards suggested improprieties in Iraq military contracts awarded to Halliburton Co., the company Vice President Dick Cheney headed before becoming vice president.

He also suggested a failed policy in Afghanistan. "The drug lords and the warlords have now come back to power," Edwards said.

"There needs to be reform of our intelligence community, but I'll save that for another discussion," he said.

Campaign aides acknowledged that having Edwards perform both roles — offering an uplifting, positive message while pushing hard in criticizing Bush — amounted to something of a balancing act.

"Right now, our view is that people are responding to a positive message, are tired of negative attacks" said Peter Scher, Edwards' campaign manager, who then added, "Obviously there are differences and we're going to continue to talk about those differences."

During the primary season, Edwards drew high approval ratings as he generally refrained from criticizing his primary opponents. In fact, some of his advisers had wanted him to be more critical of Kerry once the Massachusetts' senator became the front-runner.

Democratic strategists hope that Edwards' Southern charm and cheerfulness can help deflect GOP criticism of Kerry as overly dour and pessimistic, especially about the economy.

"Our vision is hopeful and optimistic," Edwards told the town-hall meeting. He even said he was pleased that gasoline prices seemed to have dropped after the highs reached recently. Democrats, led by Kerry, had blamed the administration for the higher gas prices.

But in his first two days of solo campaigning, Edwards also has shown little reluctance to take on the administration, citing the loss of manufacturing jobs under Bush and the ballooning federal deficit.

Bush-Cheney campaign spokesman Steve Schmidt said, "John Edwards is now traveling the country serving as John Kerry's lawyer in trying to sell that pessimistic and negative message."

The "front-porch" format, also being used by Kerry in Pennsylvania, was designed to showcase efforts by the Democrats to reach out to ordinary Americans and hear their problems.

Later, Edwards went to solid Bush country, Texas, for an evening fund-raiser in Houston that organizers said raised slightly more than $500,000 for both the Kerry-Edwards campaign and the Democratic National Committee.

He was to campaign in California on Friday.