Why such different voter drives?

Barack Obama and Hillary Clinton are taking different tacks on voter drives.

Obama is running a traditional voter drive to sign up new voters by Friday's deadline, followed by a push on one-stop voting between April 17 and May 3.

Clinton is waiting to focus on one-stop voting.

One reason for the difference could be the types of voters each campaign hopes to get. Obama's campaign has done well with college students — who often have not registered to vote before — as well as unaffiliated voters, while Clinton is focusing on a more traditional Democratic base.

Under state law, voters can register or re-register to a new party by Friday, but at one-stop sites voters who have already registered in the past cannot switch parties.

"We're bringing Republicans and Democrats and independents onto the voter rolls so that they can have a voice in the primary," said Obama spokesman Dan Leistikow.

Clinton spokeswoman Carly Lindauer said that while they are not formally signing up new voters right now, they have answered questions about registration through the N.C. Ask Me campaign.

"There is an enormous pool of unaffiliated voters, and I think those are giong to be critical to both campaigns in this election," she said.