CHARLOTTE, N.C. — “Swing state” is something North Carolinians have been hearing a lot lately.  There’s no avoiding the importance the campaigns of both President Obama and his presumptive challenger Mitt Romney place on the state and its 15 electoral votes. As tightening polls and numerous candidate visits suggest, predicting the November result is not easy.

But for the president to repeat his surprising 2008 win here – by a slim, just over 14,000-vote margin – he will have to target, expand on and get out his strongest base. That would be minority, particularly African American, voters.

What will it take for the president to make North Carolina swing his way in November? Will the Democrats’ decision to hold their national convention in Charlotte, the state’s largest city, affect enthusiasm and turnout? How much does the president’s 2012 success depend on the rise of North Carolina’s minority population? And will the economy trump everything?

“A lot of politics is demographics these days, more than ever,” said David Bositis, senior research associate at the Washington-based Joint Center for Political and Economic Studies.

Bositis, who studies minority political engagement, pointed to a change that is happening in North Carolina and across the country. He told me that the white working class, a group Obama has had trouble appealing to, “is really shrinking in the country,” while the number of non-white voters is growing.

According to census figures,  between 2000 and 2010 the Hispanic population in North Carolina more than doubled (to slightly more than 800,000) and the black population rose almost 20 percent (to two million) out of a total of more than nine and a half million residents.  Some are African Americans moving or returning to the South, for economic and cultural reasons, in what has been called a “reverse migration.”

In a record 2008 turnout, African-Americans made up 23 percent of voters here, with 95 percent favoring Obama. In exit polls, an astounding 100 percent of black women in North Carolina reported voting for the president. Obama won just 35 percent of the white vote, but he also did well overall among young and college-educated voters of all races here.

Of the voters who helped the president become the first Democrat to win the state since Jimmy Carter in 1976, “The only way those numbers will improve will be based upon population change,” said Bositis. “It’s going to depend upon the degree to which the Obama campaign decides to put resources into North Carolina,” he said.

He added, “If he does do that, if he does have a very good ground game … they will go out of their way to register as many young people, black people and Hispanic people as they can.”

“The question is ‘how energized is each candidate’s base?’” said LaTonya M. Williams, assistant professor at Johnson C. Smith University in Charlotte.

Will race matter? While Bositis said, “In Southern states, you would be foolhardy to assume that race doesn’t play any role,” he added that it matters less in a business-oriented, diverse state such as North Carolina. “Obama’s not going to bring up race; his campaign has to focus on the economy. It would be a distraction, and not a welcome distraction.”

The appeal to African-Americans may be subtle, but it’s there. The Obama campaign has opened 16 offices throughout the state, with more expected, and has organized phone banks and voter registration efforts – with a parade of celebrities offering encouragement. At a Charlotte event this year, volunteers were pumped up by Keshia Knight Pulliam, all grown up from The Cosby Show, and former Obama personal aide Reggie Love, who with his Duke basketball background brings his own state ties. Actress Angela Bassett spoke at a North Carolina Women for Obama event in Fayetteville earlier this month.