NEW ORLEANS — Things traditionally get started a little late down here, an inclination that runs from mealtimes to political races. But with nearly a year to go before the 2014 election, it is already open season on Senator Mary L. Landrieu, Democrat of Louisiana.

“Why didn’t she do her job, protect us from Obamacare from the start?” asks a new ad from Americans for Prosperity, a political nonprofit group founded by the billionaire industrialists Charles and David Koch. And a post from a conservative blog that refers to her as “MussoLandrieu,” with a picture of her face superimposed on the body of Benito Mussolini, has been making the rounds on Twitter.

Republicans are so giddy about the prospect of winning her seat that their main problem is too many of them are trying to do so. “It’s a different world than Louisiana was six years ago,” said Bernie Pinsonat, a pollster in Baton Rouge. “We do not have Democrats who win anything in this state today.”

As Democrats look across the rest of the South, the outlook does not get much better. Ms. Landrieu, along with Senators Mark Pryor of Arkansas and Kay Hagan of North Carolina, is pretty much all that is left of Southern Democrats in the Senate.