Record numbers of voters across the nation are casting ballots before election day, including high proportions of Democrats and African Americans in some of the battleground states in what appears to be a promising sign for Barack Obama.

In North Carolina, which hasn’t gone for a Democrat for President since Jimmy Carter in 1976, almost a million people have voted, and Democrats outnumber Republicans by 2 to 1.

“We’re going to bust every record we’ve ever had,” Gary Bartlett, executive director of the State Board of Elections, said of the state’s early-voting participation.

In past campaign seasons, Republicans have used early voting to their advantage, mobilising a slice of the electorate that typically skews their way. Yet a look at voters in crucial states suggests that Obama is turning out his base in numbers that surpass those of Republican John McCain.

“Historically, we’ve seen that early voters are older, they tend to be white, have higher incomes and are better educated,” said Paul Gronke, director of the Early Voting Information Center in Portland, Ore.

Early voting continues in many states, so the numbers can change. But Obama seems well-positioned in several Republican-leaning states that have the potential to broaden his path to the magic number of 270 electoral votes.