(CNN) -- Sen. John McCain this week begins a bus tour of five states that he says helped shape his views and make him the politician who will carry the GOP torch in the upcoming presidential election.
Sen. John McCain is kicking off a bus tour through five states this week.
The presumptive Republican nominee heads to Mississippi on Sunday, where the tour kicks off the following day.
McCain will swing through Virginia, Maryland, Florida and Arizona in the upcoming week.
According to campaign officials, the purpose of the tour is to "introduce John McCain to the American people in an intimate way," and add significance to his "remarkable American tale."
McCain is now trying to style himself as the most attractive option for voters in November, while Democratic rivals Hillary Clinton and Barack Obama are still in a delegate-by-delegate battle to become their party's nominee.
Clinton this weekend shot down calls by Obama backers to drop out of the race, and Obama said Clinton should remain in race "as long as she wants."
Obama leads Clinton in total delegates 1,625 to 1,486, but it's likely neither candidate will get the necessary 2,024 delegates needed to clinch the nomination before the Democratic National Convention in August.
Two of Obama's leading supporters, Sens. Christopher Dodd and Patrick Leahy, said Friday that Clinton should rethink her chances of overcoming that deficit and consider folding her campaign.
Leahy, of Vermont, said Clinton "has every right, but not a very good reason, to remain a candidate for as long as she wants to."
Speaking in Johnstown, Pennsylvania, Obama said he did not discuss Leahy's call for Clinton to drop out with the Vermont senator, who serves as chairman of the Senate Judiciary Committee.
"My attitude is that Senator Clinton can run as long as she wants," the Illinois senator said. Watch what Obama says about Clinton's campaign »
Tennessee Gov. Phil Bredesen on Sunday said he thinks the prolonged Democratic race is hurting his party "tremendously."
"At the end of August, come Labor Day, we're going to have a nominee, but if it's the nominee of a divided party and an emotionally exhausted party, there's just not time to conduct the kind of campaign we need to have," he said on "Fox News Sunday."
"We can win this election, but we're making it -- that way a lot steeper and rockier road than it needs to be."
The race could come down to the superdelegates, a group of about 800 Democratic party leaders who cast their vote at the convention and are free to pick the candidate of their choice.
Bredesen has been calling for a superdelegate convention before the national convention.
"If it comes down to the superdelegates -- and I don't think anybody wants that to happen, but if that's what it is, it just seems to me common sense to try to move that decision back earlier into June," he said.
A CNN/Opinion Research Corp. poll released Thursday suggests that the bickering between Clinton and Obama could affect Democratic turnout in November.
One in six Clinton supporters said they would not be likely to vote in November if Obama gets the nomination; an equal number of Obama's supporters said the same about Clinton.
Obama called fears that the Democratic Party would be damaged by a long campaign "somewhat overstated." But he added that both he and Clinton should avoid campaign attacks "that could be used as ammunition for the Republicans" in November.
Meanwhile, McCain has already launched his first general election ad, in which he is portrayed as an experienced, strong and patriotic leader.
In what appears to be a shot at Obama's message of change, campaign officials said the purpose of the ad is to show "John McCain has the experience to make change," echoing a line that Clinton has used on the campaign trail.
Throughout the 60 second spot, images of McCain now, and during his days in Vietnam, flash across the screen while newspaper headlines superimposed behind the video call him an image for the future, "a real hero," "ready on day one."
The ad will air for now in the battleground state of New Mexico which carried Al Gore in the 2000 elections and flipped to George Bush in 2004 -- a sign the presumptive nominee will focus heavily on the swing states this fall. E-mail to a friend
CNN's Emily Sherman contributed to this report.