Flip on TV and prepare to hear an ad attacking Democrat Sen. Kay Hagan — evidence of the multimillion-dollar air war launched months ago by Americans for Prosperity, a conservative group backed by the billionaire Koch brothers.

But don’t be fooled to see barely a yard sign in the state capital. The fight on the ground for Hagan’s seat might be cheaper, but it’ll be just as fierce — and both sides are already gearing up for it.

Unions are tapping into the networks of community groups. Planned Parenthood has promised to repeat the same successful game plan it played against Ken Cuccinelli in Virginia this year. And the Democratic Senatorial Campaign Committee and Hagan are promising boots on the ground.

Conservative groups, meanwhile, say they will do more than air ads. They’re promising a more sophisticated ground game than they’ve ever run — an attempt to match the strength of the turnout operations of unions and other liberal groups.

The two-front war in North Carolina — on the air and on the ground — is sure to make the race one of the hardest fought in 2014. And not only is it a state to watch as Republicans attempt to retake the Senate this year, it’s also an early test of get-out-the-vote operations in a battleground state ahead of 2016.