Democratic Sen. Joe Manchin III has quickly become a favorite of Republicans with his quest to delay the individual mandate to buy health insurance under Obamacare.

Though that effort doesn’t seem to have much traction, it’s one that could start giving vulnerable Democrats heartburn.

The West Virginian announced Wednesday that he is working with Georgia GOP Sen. Johnny Isakson to craft a one-year delay of the insurance requirement of the landmark health care law. That idea has already picked up the endorsement of Michelle Nunn, the Democrat seeking Georgia’s open Senate seat in 2014.

“It has become apparent in recent weeks that implementing this law will take some time. That’s why I supported a delay in the mandate on businesses,” Nunn said in a statement. “And it is why, I believe that in light of the recent implementation challenges, I agree with bipartisan efforts led by Georgia Senator Johnny Isakson to postpone the insurance penalty for Georgia families.”

But many incumbent Senate Democrats — even some from conservative-leaning territories — have shown far less favor to the year delay, despite the deeply troubled rollout of the government website intended to help the uninsured buy coverage.

North Carolina Democratic Sen. Kay Hagan says the administration should waive the tax penalty for not having coverage during what she says should be a two-month extension of the open enrollment for the new exchanges.

“I am asking the Administration to extend the open enrollment period by two months, and waive the penalty for the individual mandate for the same period of time, to make up for time that is being lost while the website for the federal exchange is not functioning,” Hagan said in a statement.

Hagan is one of 10 Democratic senators, led by Jeanne Shaheen of New Hampshire, who have signed on to a letter calling for the Obama administration to extend open enrollment further into 2014. The letter was a reaction to widespread reports of people being unable to use the HealthCare.gov website successfully.

An aide to Sen. Michael Bennet said that his boss is simply seeking an extension of the enrollment period. The Colorado Democrat was one of the senators who signed the letter and isn’t up for re-election this cycle.

Fellow signatory Mark Begich of Alaska explicitly opposes the full-year delay of the individual mandate, an aide said Friday. Begich would like to see the current yearlong delay on the employer mandate extended for an additional year, however.

This may all prove to be a moot point, with the Obama administration signaling Friday that it expects the troubled HealthCare.gov to be fully up and running for most users by the end of November, well before insurance coverage is set to begin.

Senate Democratic leadership has taken a wait-and-see approach, looking for cues from the administration as to how to proceed on any legislative effort that might make changes to the health care law.

Even though they are frustrated by Manchin and his public campaign to delay the mandate — including on Fox News Channel’s “The O’Reilly Factor” — they are not yet prepared to respond in any way.

First, Manchin has yet to produce legislative language and has not announced any Democratic co-sponsors.

An aide to Sen. Dan Coats said the Indiana Republican has invited Manchin to sign on to a proposal that Coats has already written. It would delay the individual mandate for a year and put into law the Obama administration’s executive action delaying the employer mandate for a year.

Second, much of the recent uptick in congressional complaints against the health care law and the individual mandate has been spurred by the failures of HealthCare.gov in the first few weeks of its operation.

President Barack Obama in an Oct. 21 Rose Garden speech vowed that the website would be upgraded so that more Americans could buy insurance with less hassle.

Senate aides say they are waiting to see whether the president lives up to his promise and what changes they might need to push outside the administration’s efforts in the weeks and months ahead.

Florida Republican Sen. Marco Rubio is pushing his own plan to stall the mandate until six months after the Government Accountability Office certifies that HealthCare.gov is functioning as intended.

“I think we’re going to continue to have a debate about the merits of Obamacare. All this says is we should not be penalizing anybody until this website is working because that is the main way we’ve told people they’ll be able to get health insurance,” Rubio said Friday on CNN.

Of course, the potential of a Manchin-backed amendment on the floor might create a bigger political quagmire than any of the strictly GOP proposals, given Republican opposition to the underlying law.

Vulnerable Democrats, such as the ones who signed on to Shaheen’s letter, could face a political quandary. If they support a one-year delay, they could be accused by groups such as the National Republican Senatorial Committee of being flip-floppers who are running away from their original votes to create the law. If they oppose it, they could be accused of penalizing people who, through no fault of their own, were unable to sign up for health insurance.

If Democratic leaders in fact follow the administration’s lead on this issue, it’s very unlikely they will support delaying the cornerstone of the health care law while they’re under siege politically from Republicans. But either way, Manchin has created political exposure for his colleagues on a bill that has a near-impossible path to becoming law.