For months, Sen. Mary Landrieu had been honing her message on Obamacare in advance of a tough 2014 re-election bid in Republican-leaning Louisiana.

Then, in November, Americans for Prosperity, a conservative group funded by the billionaire Koch Brothers, ran a scathing ad accusing Landrieu of “backtracking and avoiding accountability” in her support for Obamacare. The ad buy was big and aired widely, and Landrieu's team felt compelled to offer a more full-throated explanation of where she stood on the new health care law.

So Landrieu launched her first ad of the mid-term elections in December — nearly a year ahead of election day — portraying herself as someone prepared to fix, rather than abandon, the health care law. The ad includes news clips of Landrieu talking about legislation she introduced to allow millions of Americans who had health plans canceled to keep those plans indefinitely.

“I’m fixing it, and that’s what my bill does, and I’ve urged the president to fix it,” Landrieu said in the ad. Seemingly turning on President Obama, a fellow Democrat, Landrieu added, “This is a promise you made, this is a promise you should keep.”

Mark Putnam, one of the Democratic Party’s top media consultants for statewide and national races, oversaw the ad's production, and Landrieu’s campaign spent $250,000 broadcasting it everywhere in the state except the Democratic stronghold of New Orleans, where Landrieu’s brother is mayor.

Even as Obama and Democrats were suffering politically under the glitch-riddled Obamacare rollout, Landrieu stepped firmly into the debate — not away from it — offering an early peek at how vulnerable Democrats will try to frame their support for Obamacare to inoculate themselves against Republican attacks.

The Democratic play? Present themselves as the ones trying to fix the troubled health care law, and Republicans as the ones who will let it flail indefinitely.

“If you took action and took a stand, why not advertise it?” said J.B. Poersch, a managing director for SKDKnickerbocker and one-time executive director of the Democratic Senatorial Campaign Committee. “I think it levels the playing field.”

Landrieu's bill, which never got a vote because the White House adapted the concept in its own fix, quickly won the backing of two other at-risk Democrats: Sens. Kay Hagan of North Carolina and Mark Pryor of Arkansas, who will almost certainly tout their support for the fix during their own re-election campaigns.

Landrieu, Hagan and Pryor are among the vulnerable Democrats who have navigated tricky political terrain as the health care law took effect, with little warning from the White House about the problems the law faced. All three have been attacked by Americans for Prosperity and other outside groups for their support of Obamacare.

Although Democratic outside groups have come to the lawmakers' aid with supportive television ads, only Landrieu’s campaign has so far crafted an official campaign ad in its defense. (Pryor’s early campaign ad touts his support for a much less controversial doctrine: the Bible.)

But other Democrats in competitive races will likely follow Landrieu’s lead when they face campaign-trail questions about the law.

“Democrats will continue to highlight the differences between them and their opponents” on health care, said DSCC spokesman Justin Barasky — particularly Democrats' new willingness to refine the law. “Polls show that’s a winning message.”

Indeed, most Americans favor changing the law rather than eliminating it entirely, as Republicans have widely proposed.

But the GOP is changing its tune. As implementation of the law continues, Republicans are beginning to propose strategies of their own to help improve Obamacare rather than simply pushing repeal.

“You’re going to see a lot more Republicans talk about the solutions we want to put in place that are more market-driven,” said Republican National Committee spokesman Sean Spicer.

Republicans have yet to coalesce around any of the multiple health care plans percolating in Congress. But there is overwhelming consensus that, as candidates, they should remind voters which party originally supported the health care law.

“For Democrats, it’s the equivalent of robbing a bank and then figuring out how to get the money back,” said the RNC's Spicer.

Republicans view Landrieu’s ad as the perfect example of what they see as Democratic hypocrisy.

“I think this is covering your tracks in the most amazing way I've ever seen,” Jason Meath, a political media consultant with Meath Media Group who is currently advising Liz Cheney's Wyoming Senate campaign. “She threw Obama under the bus.”