WASHINGTON (CNN) -- Sens. Barack Obama and Hillary Clinton traded shots Thursday over the former first lady's recently released White House schedule, while also tackling key campaign issues in states holding primaries in May.
Clinton's arrival in Indiana was marked by a warm embrace on a sunny airport tarmac from her highest-profile supporter in the state, Sen. Evan Bayh, who is also the campaign's national chairman.
It was an auspicious start for Clinton in Indiana, which borders Obama's home state of Illinois.
Even so, the campaign is confident that Hoosier voters see Clinton as best equipped to handle the economy, as primary voters did in Ohio on March 4.
"We see Indiana as a very competitive state," Clinton spokesman Doug Hattaway said. "Like Ohio and Pennsylvania, the economy is top issue we see. We feel like voters are in a place where they do see her as the candidate who can turn it around."
Hattaway said Indiana had lost 9,000 manufacturing jobs in the past year and ranked 10th in the nation in home foreclosures.
The campaign sees West Virginia and Kentucky as upcoming contests that could trend toward Clinton because of similar economic and demographic reasons. West Virginia holds its primary May 13; Kentucky votes May 20.
But the issue of Clinton's support of NAFTA, according to the Obama campaign, could cause a problem for voters in these working-class states.
A senior adviser to the Obama campaign said Thursday that newly released White House records, which Obama has urged the senator to release, reveal that Clinton misled voters on her NAFTA position during her time as first lady.
The New York senator "owes an apology to the people of this country," Obama adviser David Axelrod said during a Thursday conference call with reporters.
"This is a question of character," he said, adding that voters "have to wonder if this was one of the reasons she was reluctant to get these records out there on a timely basis."
Obama's campaign used the release of Clinton's White House schedules Wednesday -- which showed her attending NAFTA strategy meetings in advance of its approval by Congress -- to suggest that Clinton had not been telling the truth to voters and that she was a "vocal supporter of NAFTA." Watch more on Clinton's White House records »
Clinton responded Thursday: "At the time, as many people have confirmed ... I spoke out about the concerns about NAFTA," she said. "And now as a candidate for the presidency I have been very clear about what I would do to renegotiate NAFTA. I have been consistent, unlike Sen. Obama, who has not been."
Earlier Thursday, Clinton wasted little time taking on tough policy issues facing the nation. Her first stop was held in a cramped diner in Terre Haute, where she held a roundtable with locals.
"It's outrageous to me that we're more dependent on foreign oil today than we were on 9/11," she said. "And we have just let this go on and on without taking any steps, without holding anybody accountable. ... It just can't continue."
Just east of Clinton's event, Obama appeared at a rally in Charleston, West Virginia, alongside the state's Sen. Jay Rockefeller and Gov. Joe Manchin.
He discussed the effect of war on the economy.
"At a time when we're on the brink of recession, when neighborhoods have 'For Sale' signs outside every home and working families are struggling to keep up with rising costs, ordinary Americans are paying a price for this war as well," Obama said. "It is not the same price as our troops and their families, but it is a price." Watch Obama's speech in West Virginia »
His comments come on the same day a Gallup daily tracking poll showed Clinton holding a 7 percentage point lead over the Illinois senator, 49 to 42 percent. That lead is outside the poll's statistical margin of error of 3 points, the widest gap between the two candidates in weeks and the first time Clinton has been in the lead since February.
The poll was conducted March 14-18, almost entirely before Obama gave a widely praised speech on his relationship with the Rev. Jeremiah White and race relations in America.
Obama said Wednesday that the recent uproar over his former pastor's sermons has reminded him of the odds he faces in winning the White House. Watch more of the one-on-one interview »
Controversy also swirled around a report in the New York Times that said Clinton's aides may be pushing the Wright issue to woo superdelegates.
"Developments on either side will weigh into people's thinking. That's obviously been a development. ... The superdelegates are going to look at it the way a lot of voters do. Who's going to win this thing? Who is going to make the best president?" Hattaway said.
Another issue plaguing both campaigns was the question of a revote in Michigan, though CNN has confirmed that the state Senate failed to vote on holding a new primary June 3.
It now appears that the state's 157 delegates might not have a say in selecting their party's presidential nominee.
The Legislature is in recess for two weeks, and by the time lawmakers return, it would be too late to approve and organize a new vote.
Shortly after the announcement, the Obama campaign released a statement that said, "we support a fair solution that allows Michigan democrats to participate at our National Convention this summer, and we look forward to working with the Michigan Democratic Party and the DNC to achieve that goal. Senator Obama looks forward to building a winning campaign in Michigan in the fall as our Democratic nominee." Watch Obama react to Michigan news »
Earlier Thursday, Clinton blasted Obama over his reluctance to approve a primary revote in Michigan.
"I have, as the Democratic National Committee has, come out in favor of any effort to re-vote in Michigan," she said. "I do not understand what Sen. Obama is afraid of."
Michigan and Florida held primaries in January, but the Democratic National Committee stripped them of their delegates for scheduling their contests too early.
Obama has said that he wanted the delegates of Michigan and Florida seated. E-mail to a friend
Alex Mooney, Ed Hornick, Peter Hamby, Rebecca Sinderbrand and Mike Rosselli contributed to this report.