"2014 is shaping up to be a referendum on the badly damaged Republican brand that's gotten worse in recent months after nearly every Republican senate candidate supported a reckless and irresponsible shutdown championed by NRSC Vice Chair Ted Cruz," Barasky said in an emailed statement.
In Arkansas, however, Republican Rep. Tom Cotton, seems to be zeroing in on Obamacare and setting up his campaign as a referendum against the law.
"My opponent Senator Pryor has insisted on pushing ahead with this flawed law and has opposed any delay. The roll out of the healthcare.gov and state exchange sites have exposed numerous problems, including a lack of privacy guarantees for consumers," Cotton said in an emailed statement. "This issue will be a prominent one in our campaign."
The Club for Growth also has made the Affordable Care Act a centerpiece of their campaign against vulnerable Democrats, including Pryor. The group launched a six-figure ad buy in the early days of October criticizing the two-term senator for opposing any delays to the law as a part of a broader budget deal to reopen the government when it was shut down.
But Pryor is striking back, painting his opponent as an extremist who brought the country to the brink of financial ruin for a strategy that never stood a chance.
"Mark is as frustrated as anyone about this, and the administration needs to fix it. Maybe Congressman Cotton thought he'd help this problem by voting to shut down the government," says Erik Dorey, a spokesman for the Pryor campaign.
In North Carolina, Hagan has continued to support the Affordable Care Act, but she has distanced herself from one component.
Hagan signed onto a bill that would repeal the medical device tax, a 2.3 percent tax on medical tools that is expected to raise $30 billion over 10 years. The tax has been a rallying cry of Republicans who say it hurts business.
Hagan is one of three Democrats running in 2014 for reelection who has signed onto the bill.
"My number one priority is getting North Carolinians back to work, and I am concerned about the effects of the planned medical device tax in North Carolina," Hagan said in a statement. "The medical device industry is critical to North Carolina's dynamic bioscience economy and when the tax was first proposed, I opposed its adoption. Democrats and Republicans must now work together to find a solution that does not harm our economic recovery."
Others have taken a different tack, getting out in front of the law and continuing to campaign for its success. Landrieu pledged to go to the mat for Obamacare in 2014 just last week.
During a floor speech, Landrieu blasted Republicans for trying to tie a repeal of the Affordable Care Act to a funding bill. She insisted that the time to fight for Obamacare would be 2014 and she encouraged Republicans to give it all they have.
"We did not wake up one morning and declare this the law. The people of the United States declared this through us as their Representatives. If they do not like it, they can unelect us. Believe me, they will have a great chance because I am up for reelection right now," Landrieu said. "I am standing in this election as a supporter of the Affordable Care Act–not because it is a perfect law but because it is much better for all the people I represent than what we had before."