Seven weeks after’s troubled launch, President Obama has turned his emphasis from apologizing for the problems to criticizing Republicans for attempting to undermine his signature health-care law.

But the strategy presents difficult challenges for Obama, who is seeking to refocus Americans’ attention on the benefits of the Affordable Care Act as the administration works on fixing the online enrollment system.

Insurers and insurance commissioners, who are among the groups most closely invested in the program’s success, are questioning the Obama administration’s approach to it. The president’s own credibility with the public has ebbed in the wake of the rocky rollout. And some of the strongest arguments for the law — that it could contain health-care costs over time and ease the financial burden on hospitals required to treat uninsured patients — are longer-term benefits that are harder for the public to easily comprehend.

On Wednesday, for example, the White House Council of Economic Advisers suggested that the legislation had helped slow the growth in health-care spending, in part because it helps reduce Medicare overpayments to private insurers and medical providers.

“The slowdown is indisputable,” CEA Chairman Jason Furman told reporters in a briefing. “A very important part of the slowdown is structural, and a very important part of that structural story is the Affordable Care Act.”

Yet even as Furman announced those findings in the Eisenhower Executive Office Building, the insurance industry’s largest trade association sent out a press release blasting the same provisions he was touting.

The program at the heart of the dispute, Medicare Advantage, covers more than a quarter of Medicare beneficiaries under private plans, but is being curtailed because of high costs. Karen Ignagni, president and chief executive of America’s Health Insurance Plans, complained in a letter Wednesday that the program “is facing a future of severe underfunding due to a combination of legislative and regulatory actions in recent years.”

Insurers are theoretically aligned with the White House in the effort to sell the new health-care law, because they’re eager to enroll customers. But it’s an uncomfortable partnership, as each side has accused the other of putting consumers in a difficult position when it comes to the cancellation of health plans sold on the individual market.

Other traditional White House allies in this fight are state insurance commissioners, many of whom consider the law as critical to expanding health-care coverage for their residents. But commissioners, who met with Obama on Wednesday at the White House, say they were caught off guard by his proposal to extend the sale of individual plans that don’t meet the bedrock requirements of the Affordable Care Act.

Even as he takes friendly fire on the legislation, the president must manage a busy schedule as he seeks to promote other high-priority policy initiatives. On Tuesday, he met with a bipartisan group of senators at the White House in a two-hour session designed to try to persuade them to hold off on new sanctions against Iran, with a second round of negotiations to freeze the country’s nuclear program set to begin this week.

Obama’s problem with messaging is not the only consequence of a schedule crowded with ceremonial events and the delicate foreign policy issues. He also faces a consistency problem.

Last week, the president offered a highly self-critical view of the disastrous health-care rollout, saying several times that the poor result is “on me.”

His appearance before the news media followed an apology to Americans who are receiving insurance cancellation notices, something he had repeatedly assured the public would not happen. His trustworthiness — for which the public always gave him high marks — has plummeted, according to recent polls.

But on Tuesday, Obama emphasized to a group of Wall Street executives that he alone is not to blame. He shifted some of the responsibility to Washington’s political dysfunction — a problem he pledged as a candidate to resolve — and to the Republican Party.

Obama described what he called the Republicans’ “ideological resistance to the idea of dealing with the uninsured and people with preexisting conditions” in any health-care reform. He suggested that he underestimated the depth and enduring nature of that sentiment, more than three years after the law’s passage.

“We should have anticipated that that would create a rockier rollout than if Democrats and Republicans were both invested in success,” Obama said. “One of the problems we’ve had is one side of Capitol Hill is invested in failure, and that makes, I think, the kind of iterative process of fixing glitches as they come up and fine-tuning the law more challenging.”