Sometimes the battle lines in a campaign for Congress could hardly be clearer. To wit: Florida's 13th district special election.

Call it the battle of the "lobbyist" label vs. the "Obamacare" tag.

Outside groups are up on the air with opening salvos in this battleground district. Democrats are going squarely after Republican David Jolly's record as a lobbyist. Republicans, meanwhile, are taking aim at Democrat Alex Sink's support for for the new health-care law.

The National Republican Congressional Committee launched its first TV ad Wednesday. Just seven seconds in, it points to the law.

"Alex Sink supports Obamacare, even though 300,000 Floridians could lose their health insurance plans because of it," says the narrator of the commercial, which is backed by an initial $230,000 buy.

The Democratic Congressional Campaign Committee released its first ad on Tuesday. The word "lobbyist" or "lobbying" comes up five times in 30 seconds.

"Lobbyist David Jolly's proud. We pay the price," says the narrator. The DCCC is spending about $200,000 to air the ad.

Republicans are dead set on making the race a referendum on Obamacare, which polls shows remains unpopular in the wake of a rocky rollout. Sink favors repairing the law rather than repealing it.

"My approach would be, let’s take what we have and fix the things that are wrong and make them work,” she told The Washington Post in a recent interview.

Democrats want to cast Jolly as a Washington insider and associate the often toxic "lobbyist" label with him in the minds of voters.

In an interview earlier this month, Jolly said he is “proud of the fact” that he knows “how to work with a very complex federal government.”

The 13th district is a key early message testing area for the fall midterms because it's evenly divided. President Obama carried it twice, but it was long represented by a moderate Republican, late congressman C.W. Bill Young, Jolly's old boss.

For Democrats in particular, the weeks leading up to the March 11 election will be crucial. Sink is not tethered to the health-care law like many other Democratic congressional candidates. She has no vote on the matter and is from outside Washington.

If Republicans can nonetheless defeat her by tying her to the law, it could be a long midterm cycle for the Democratic Party.