Before the Pennsylvania primary, pundits said Sen. Hillary Rodham Clinton couldn't just win the Keystone State, but that she had to do so convincingly to justify staying in the race for the Democratic presidential nomination.

Two weeks and an impressive Clinton victory later, it's widely believed that the New York senator got the kind of win she needed.

Some in the media had claimed that Pennsylvania, an older state largely comprised of rural, blue-collar workers, was tailor-made for Clinton demographically. That, paired with the fact that polls showed her with leads as large as 20 points just weeks before the contest, put pressure on the Clinton campaign to perform well in the state's primary.

Now Sen. Barack Obama is feeling a very similar pressure in the state of North Carolina, which goes to the polls Tuesday.

Obama, who garnered more than 90 percent of the black vote in the Pennsylvania primary, is heavily favored to win the Tar Heel State, where more than 40 percent of its Democratic voters are black.

When the Illinois senator routed Clinton in South Carolina on Super Tuesday, he got a boost by garnering about 80 percent of the black vote - a constituency that accounts for about 55 percent of the state's Democratic voters.

But because North Carolina's demographics give Obama a strong edge in the state, some say he needs to win in a convincing fashion to stop Clinton from claiming a moral victory if she keeps the race close there.

"Obama hasn't won a primary or a caucus in about a month now," said Nathan Ashworth, chapter coordinator of Students for Obama at Ball State University. "It's not necessarily a bad thing, but I definitely think there's a little bit of pressure."

Robert Jones, chair of the political science department at Belmont Abbey College in North Carolina, said a close race in the state may raise concern among superdelegates - a group of uncommitted party officials who each get a non-binding vote to select a nominee - that Obama can't easily win an area that favors him demographically.

"The superdelegates will have questions," Jones said when asked what would happen if Obama doesn't win the state by a comfortable margin. "They would like to start pushing for November, but they can't."

Because of the highly contested race taking place in Indiana the same day - polls show the candidates in a dead heat there - a small win by Obama or an upset victory by Clinton in North Carolina could completely shift the momentum of the race.

Louis Ayala, an analyst and political science professor at Notre Dame, said a recent attack advertisement released by the North Carolina Republican Party could close the gap between the candidates in that race.

"If you get a voter who still hasn't made up his or her mind, it probably does hurt Obama," Ayala said, referring to an ad in which Obama's former pastor is shown making an anti-American statement. Following the clip, the ad concludes by saying that Obama is simply "too extreme for North Carolina."

Ayala said the advertisement is an example of Southern Strategy, a type of advertising that draws upon racial sentiments with voters in the South.

Still, Averell Smith, the director of Clinton's North Carolina campaign, suggested that a Clinton victory was unlikely in the state.

"To win here would be the upset of the century," he told The Washington Post.

Justin Tresnowski, president of Notre Dame's chapter of Students for Obama, downplayed the significance of winning by a certain margin.

"The truth is that every single vote matters and every single delegate matters," he said. "Rather than trying to meet some sort of expectation set by the media or the Clinton campaign, I'm sure the Obama campaign is trying to win as many votes as it can."