Outside money is pouring into North Carolina's races.
N.C. State political science professor Andy Taylor sees several reasons why third-party groups are spending millions attacking U.S. Sen. Elizabeth Dole and Republican gubernatorial nominee Pat McCrory.
Close Races: Polls in both the Senate and gubernatorial races are closer than expected, giving national groups hope that they can influence the outcome with a well-timed ad.
Stand by Your Ad: Part of a 2002 campaign law requires candidates to personally approve their ads, but outside groups can run harsh attacks without a backlash.
Contribution Limits: State and federal laws limit the amount donors can give directly to candidates, so some give to third-party groups to further their efforts.
Taylor says that the increasing influence of third-party ads means candidates have less control over their message, but they gain "plausible deniability" on attacks.
"You lose control, which is problematic," he said. "But at the same time, the hits can come in and they're at more than arm's length."
He said the current system is an imperfect compromise.
"I think it's a compromise — satisfactory or not — between two competing values: to make elections transparent and fair but at the same time allow our citizens to participate as much as they want," he said.