WASHINGTON: With the hourglass running out for his administration, President Barack Obama’s health care law is struggling in many parts of the country. Double-digit premium increases and exits by big-name insurers have caused some to wonder whether “Obamacare” will go down as a failed experiment. If Democrat Hillary Clinton wins the White House, expect her to mount a rescue effort. But how much Clinton could do depends on finding willing partners in Congress and among Republican governors, a real political challenge. “There are turbulent waters,” said Kathleen Sebelius, Obama’s first secretary of Health and Human Services. “But do I see this as a death knell? No.” Next year’s health insurance sign-up season starts a week before the Nov. 8 election, and the previews have been brutal. Premiums are expected to go up sharply in many insurance marketplaces, which offer subsidized private coverage to people lacking access to job-based plans. At the same time, retrenchment by insurers that have lost hundreds of millions of dollars means that more areas will become one-insurer markets, losing the benefits of competition. The consulting firm Avalere Health projects that seven states will only have one insurer in each of their marketplace regions next year. Administration officials say insurers set prices too low in a bid to gain market share, and the correction is leading to sticker shock. Insurers blame the problems on sicker-than-expected customers, disappointing enrollment and a premium stabilization system that failed to work as advertised. They also say some people are gaming the system, taking advantage of guaranteed coverage to get medical care only when they are sick. Not all state markets are in trouble. What is more important, most of the 11 million people covered through HealthCare.gov and its state-run counterparts will be cushioned from premium increases by government subsidies that rise with the cost. But many customers may have to switch to less comprehensive plans to keep their monthly premiums down. And millions of people who buy individual policies outside the government marketplaces get no financial help. They will have to pay the full increases or go without coverage and risk fines. (People with employer coverage and Medicare are largely unaffected.) Tennessee’s insurance commissioner said recently that the individual health insurance market in her state is “very near collapse.” Premiums for the biggest insurer are expected to increase by an average of 62 percent. Two competitors will post average increases of 46 percent and 44 percent. But because the spigot of federal subsidies remains wide open, an implosion of health insurance markets around the country seems unlikely. More than 8 out of 10 HealthCare.gov customers get subsidies covering about 70 percent of their total premiums. Instead, the damage is likely to be gradual. Rising premiums deter healthy people from signing up, leaving an insurance pool that’s more expensive to cover each succeeding year. “My real concern is 2018,” said Caroline Pearson, a senior vice president with Avalere. “If there is no improvement in enrollment, we could see big sections of the country without any plans participating.” If Republican Donald Trump wins the White House, he’d start dismantling the Affordable Care Act. But Clinton would come with a long list of proposed fixes, from rearranging benefits to introducing a government-sponsored “public option” as an alternative to private insurers. Not all her ideas would require congressional action. “She is going to find it important to continue to expand health care,” said Joel Ario, a former Obama administration official who’s now with the consulting firm Mannatt Health. People in the Clinton camp say she recognizes that as president she’d have to get Obama’s law working better, and is taking nothing off the table.