No policy proposal more sharply divided Barack Obama from Hillary Clinton than the former first lady's plan requiring adults to purchase health insurance.

But as the one-time rivals head to Unity, N.H., on Friday, a health adviser to the presumptive Democratic nominee is signaling that Obama's plan could eventually go in Clinton's direction.

"Senator Obama is willing to consider any sort of proposal that would bring together, not just the insurance industry but . . . the consumers themselves," said Obama adviser Dr. Kavita Patel.

Obama's surrogate made her comments Wednesday while representing him at a National Journal health-policy forum moderated by Ron Brownstein, the political director of Atlantic Media.

Patel's individual mandate remarks were made in response to an insurance industry leader suggesting at the same forum that insurers will oppose Obama's plan as currently structured. Insurers are worried that the Illinois Democrat has not tied an individual mandate to "guaranteed issue," the industry's term for requiring patients to be covered without regard to pre-existing conditions.

"We've had the conversation about . . . guaranteed issue," said Karen Ignagni, the president and CEO of America's Health Insurance Plans. "But we are prepared to have that conversation in the insurance industry if the politicians are ready to stand up and say we are going to get everyone in."

Ignagni's words are watched closely because the organization she heads emerged from the Health Insurance Association of America, sponsors of the "Harry and Louise" ads which played a critical role in killing Clinton's effort to reform health-care in the 1990s

Asked if Obama would be seen as reversing himself if he were to endorse an individual mandate after clashing with Clinton on the issue, Patel dismissed the concern.

"He has not said he is opposed to it," Patel told ABC News. "He has voiced his disagreement with having that be a part of his health-care plan last year. But he is not opposed to the idea itself." Patel added that the Obama campaign is in touch with former Clinton health-care advisers.

If Obama were to endorse an individual mandate, Ignagni's comments suggest that it would dramatically improve his chances of getting the insurance industry to accept his call for guaranteed issue.

Community rating, however, might still be a stumbling block.

Richard Kirsch, the head of "Health Care for America Now," told ABC News in a separate interview that the liberal coalition he leads would go along with an individual mandate only if the insurance industry accepts both guaranteed issue and a system of community rating in which there were no variations in premiums on the basis of age, gender, or pre-existing conditions.

Kirsch said his group would only accept premium variations on the basis of geography.

"We're not going to get the kind of change we need by playing footsie with the industry," said Kirsch. "If they are going to change their tune, great. But I think they are only going to change their tune if they are forced to do it."

Asked if insurers would support community rating if an individual mandate were in place, an industry spokesman said such a proposal requires further examination.

"That is not something that we have come out in support of at this time," said Robert Zirkelbach, a spokesman for America's Health Insurance Plans.

UPDATE:

Concerned that some may view Dr. Kavita Patel's remarks as a sign that Barack Obama is shifting his stance on an individual mandate, a campaign spokesman told ABC News that the presumptive Democratic nominee "does not have plans to change his health care plan."

"Senator Obama does not have plans to change his health care plan, which will achieve universal coverage," Obama spokesman Bill Burton tells ABC News. "As he has consistently said throughout this campaign, he will bring together businesses, the medical community and members of both parties around a comprehensive solution to this issue."

Obama may gain politically in the short run by talking about the benefits of guaranteed issue without the burden of an individual mandate. No one wants to be required to purchase insurance that they may not be able to afford.

But close observers of reform efforts see an individual mandate as essential to making good on Obama's promise to end the insurance industry's "cherry picking" of healthy customers. If the uninsured are not required to purchase insurance while knowing that they are guaranteed access at a community-rated price, the insurance industry worries that the uninsured will only seek coverage once they become sick.