WASHINGTON (CNN) -- Sens. Hillary Clinton and Barack Obama stumped for last-minute votes in Indiana and North Carolina Friday ahead of the states' Tuesday primaries.
In CNN's "poll of polls" released Friday, Obama is leading Clinton in North Carolina by 10 points: 50 percent to 40 percent, with 10 percent unsure.
The polls were taken April 28 through May 1 of likely Democratic primary voters, and consist of three surveys: Zogby (April 30-May 1), Research 2000 (April 29-30), and Mason-Dixon (April 28-29).
A margin of error for the poll of polls cannot be accurately calculated.
"We are seeing terrific support all across Indiana and all across North Carolina ... I have no doubt these are going to be tight races. This campaign has been tight throughout," Obama said in Indianapolis, Indiana, Friday morning.
"But I am very confident the American people are looking for the kind of truth telling and serious policy making that is going to have an affect on heir lives, and as long as I'm talking about the issues."
Obama attended the North Carolina Democratic Party Jefferson Jackson dinner in Raleigh, North Carolina, Friday night -- along with Clinton.
Clinton held a morning event in Kinston, North Carolina, where she stood along side Gov. Mike Easley, who has endorsed her, along with Democratic Rep. Sheila Jackson Lee of Texas.
Clinton asked members of Congress to take sides in the gas tax holiday debate and spoke about the importance of Tuesday's primary. Watch more on the candidates' travels throughout Indiana and North Carolina »
"This primary election on Tuesday is a game-changer. This is going to make a huge difference in what happens going forward. The entire country, probably even a lot of the world, is looking to see what North Carolina decides," Clinton said.
Her travels come the same day that the Indianapolis Star -- the state's biggest newspaper -- endorsed Clinton.
"On the Democratic side, Hillary Clinton is the better choice, based on her experience and grasp of major issues, to confront those challenges. She earns The Star's endorsement in Tuesday's primary."
The editors also took aim at Obama, by writing, "As impressive as Obama appears, he is still in his first term in the U.S. Senate, and only four years ago was serving as an Illinois state senator. His inexperience in high office is a liability."
"Clinton, in contrast, is well prepared for the rigors of the White House. She is tough, experienced and realistic about what can and cannot be accomplished on the world stage."
But the paper also took Clinton to task on being too political, saying she "regrettably has pandered more to voters, particularly on gas prices, than Obama. Both have taken stands on free trade that give in to protectionism."
Both Democratic senators picked up new superdelegates in the past day.
The Clinton Campaign announced the support of four New York superdelegates. They include: New York Attorney General Andrew Cuomo, former Manhattan Borough President C. Virginia Fields, New York Comptroller Thomas DiNapoli and New York Assemblywoman Carmen Arroyo.
Clinton also won the endorsement of John Olsen -- president of the Connecticut AFL-CIO and former Democratic State Party Chair.
On Friday, Obama also picked up the superdelegate endorsements of former Democratic National Committee Chairman Paul Kirk of Massachusetts. He also picked up the support of John Patrick of Texas -- a DNC member, a 31-year member of the United Steelworkers as well as a vice president of the Texas AFL-CIO, according to the Obama campaign.
Superdelegates -- made up of governors, senators, House members and various other party officials or members -- are also known as "unpledged" delegates. They are free to choose the candidate they like, while pledged delegates are assigned in primaries and caucuses.
The remainder of the roughly 800 superdelegates have not publicly announced their preference.
The new superdelegate numbers are reflected in CNN's latest estimates: Obama has a total of 1, 734 delegates (Pledged: 1491, Superdelegates: 243) while Clinton has 1,597 delegates (Pledged: 1332, Superdelegates: 265).
Usually, superdelegates are an afterthought -- the nominee normally emerges before the Democratic National Convention by winning enough delegates in the caucuses and primaries to capture the nomination. Check out a list of the superdelegates »
But this year, Obama and Clinton are running such a tight race that after millions of votes and months of campaigning, neither candidate is expected to have the 2,025 delegates needed to seal the nomination before the August convention, and the superdelegates could set a candidate over the top.
Meanwhile, there's a new sign a growing numbers of Democratic primary voters may think the campaign season has passed its sell-by date.
In a new survey Friday, almost two out of three people think the marathon campaign is doing the party more harm than good.
In a Gallup poll released Friday, 62 percent of Democrats and Democratic-leaning independents say the continuing Democratic battle in the face of a Republican nomination that has been settled for weeks, hurts Democratic chances in the upcoming presidential election. That's twice as many as the 30 percent who say the extended primary season is actually helping Democratic odds of re-taking the White House.
In a similar March survey, just over half of Democratic primary voters polled by Gallup -- 56 percent said the lengthy campaign was harming the party.
The Gallup poll of 1,008 Americans was conducted April 25-27, and has a margin of error of plus or minus 4 percentage points.
Another national poll released Thursday suggests the battle for the Democratic presidential nomination between the two Democratic hopefuls is a virtual tie.
Forty-six percent of registered Democratic voters questioned in a CNN/Opinion Research Corporation survey released Thursday support Obama as their party's nominee and 45 percent back Clinton, a statistical dead heat when taking into account the poll's 4.5 percent sampling error on that specific question.
"Obama has lost his edge. Is it because of the controversy over his former pastor, Jeremiah Wright? While most Democrats have an unfavorable opinion of Wright, only 19 percent say Wright's statements have made them less favorable to Obama. More than two thirds say they've had no effect at all," says CNN Senior Political Analyst Bill Schneider. E-mail to a friend
CNN Associate Political Editor Rebecca Sinderbrand and Political Producers Ed Hornick and Alexander Marquardt contributed to this report.