(Karen Bleier/AFP/Getty Images)

Unlike members of Congress, President Obama is not obligated to sign up for a plan under his signature health-care law. But from a political perspective, the president has little choice but to opt for either the federal or state health insurance exchange by the end of the year.

The White House had announced in March 2010 that the president would enroll in an exchange in response to a political gambit by Republican Sen. Charles Grassley (Iowa), who proposed an amendment to the law that would have required Obama to buy a plan through the exchanges.

At the time, White House spokesman Reid Cherlin told USA Today the amendment was "unnecessary" and an effort to derail the law.

"The president will participate in the exchange," Cherlin said. "But let's be clear: The amendments being offered by Senate Republicans, including this one, are just a ploy to delay the bill."

On Monday, White House press secretary Jay Carney reaffirmed that Obama intended to sign up on an exchange. When asked about it, Carney replied, "I don’t have an update for you on that. I know that he will, and has said that he will -- or the White House has said that he will, but I don’t have an update."

Obama has a choice of either signing up under the D.C. exchange or the federal exchange in Illinois. When asked what the president was waiting for to sign up, and whether the media would be permitted to watch, Carney said, "I’ll get back to you."

Even from a practical standpoint, the president doesn't need insurance under the law; the White House medical team tends to the First Family. But given the level of political polarization surrounding the law, if Obama opted out of the exchanges it would provide more fodder for his opponents. It's the same sort of political calculation that prompted House Minority Leader Nancy Pelosi (D-Calif.) to declare all her aides would sign up under the law, even though she could have exempted her leadership staff.

Ron Pollack, founding executive director of the advocacy group Families USA, wrote in an e-mail that Obama's "decision to sign up for health coverage through the Affordable Care Act sends two important messages."

"First, it demonstrates the President's confidence that the healthcare.gov website has turned a corner and will function much more effectively," he wrote. "Second, it symbolically underscores his accurate belief that the Act will provide much better and more affordable health coverage than existed previously for many millions of Americans."

Many Republicans, of course, have used the very act of enrollment to attack the law. House Speaker John Boehner (R-Ohio) issued a press release and photos on Nov. 21 chronicling how he had tried and failed to sign up for insurance on the D.C. exchange; 45 minutes later his office confirmed that after a couple of other attempts, he had succeeded.

Other lawmakers are taking a more matter-of-fact approach to the process: Sen. John Hoeven (R-N.D.) said Monday that he has created an account through HealthCare.gov and is still working through the process.

Regardless of whether reporters get to watch the president to enroll online, or through a call center, one thing is clear: it's a pretty sure bet the White House will at least issue an official photo. And that picture will become one more element in the administration's relaunched campaign to win the hearts and minds of Americans when it comes to the Affordable Care Act.

Ed O'Keefe contributed to this story.