The Republican quest to repeal and replace Obamacare would end if Democratic nominee Hillary Clinton becomes president next year.

But not the debate over how to reduce Americans' hefty healthcare costs.

While millions of Americans have gained health coverage under the Affordable Care Act, the six-year-old law hit roadblocks this year as some insurers proposed big, double-digit premium increases and others announced their intent to stop selling plans in the law's new marketplaces, saying the losses are too great. Most of the co-ops, or consumer-operated-and-oriented plans, created as part of the law have shut down.

Republicans are happy to talk about shortcomings with the healthcare law and health costs that have been soaring for years. But even advocates for the law, who are typically reluctant to blame any problems on it, have been increasingly vocal about how it's still hard for many Americans to afford coverage.

"I do think affordability is the key issue and I think that's why we really do need to ensure healthcare costs are reduced ... I think that has really lagged," Center for American Progress President Neera Tanden said at a forum last month hosted by Americans United for Change.

Clinton tried hard to get health reform passed when she was first lady in the 1990s. Now that President Obama has done that, she would continue to implement his law if she wins in November. But she has shown a deep interest in more healthcare reform, proposing a number of policies aimed at making coverage more affordable.

Last fall, she released a plan to reduce prescription drug costs that included capping out-of-pocket drug expenses for consumers and requiring pharmaceutical companies to pay larger rebates to Medicare for low-income patients.

In a healthcare proposal on her campaign website, she also calls for requiring insurers to cover more doctors visits even before a patient pays the deductible and providing families with a tax credit to help pay for out-of-pocket health expenses.

And just before last month's Democratic National Convention, Clinton said she wants to create a government-funded "public option" healthcare plan to be sold in the state marketplaces.

But if she becomes president next year and starts pushing those proposals, she would face plenty of opposition from Congress and various corners of the healthcare industry.

Virtually none of the changes she has proposed to the Affordable Care Act are likely to be embraced by Republicans. And it could be difficult for a Clinton administration and Congress to find common ground on reducing drug costs, although increasing public pressure could push them toward a compromise.

"On drug pricing, one wonders if there is something they could do together, but on [the Affordable Care Act] I think the priorities she's outlined so far don't seem very appealing to conservatives," said Lanhee Chen, a Stanford University professor and former policy adviser to Mitt Romney.

The House and possibly the Senate are expected to remain in control of Republicans, who haven't typically wanted to improve the Affordable Care Act since it allows them to blame Democrats for rising costs. They're unlikely to support providing more subsidies to Americans and placing more restrictions on insurers, and they definitely would oppose any attempt to create a government-run health plan.

"If Secretary Clinton is elected, she'll double down on the same failed, top-down approach to healthcare that we've seen over the last seven years: more government, more spending, higher costs and fewer quality options," Rep. Kevin Brady, chairman of the House Ways and Means Committee, told the Washington Examiner.

"Americans don't want or need more expensive, government-controlled healthcare," Brady added.

The insurance and drug industries are also eyeing Clinton's proposals warily. The Pharmaceutical Research and Manufacturers of America blasted her drug plan, arguing it would stymie research on new drugs and reduce drug options for Medicare patients.

The insurance industry is less explicit about whether it would support Clinton's proposals, although it's unlikely to support changes requiring plans to cover more services before patients meet their deductibles. Instead, insurers want more flexibility in how they design their plans, arguing that stricter rules force them to bump up premiums, deductibles and other cost-sharing.

Insurers have long pushed to repeal the law's health insurance tax, or "HIT" tax. Clinton has expressed support for repealing a different tax, the "Cadillac tax" on high-cost plans, but not the HIT.

But the potential policy battles aren't stopping liberal supporters of the healthcare law from dreaming about what might be under a Clinton White House. For one thing, they're certain Republicans will finally stop promising to repeal it.

"If Hillary is elected, there is zero credibility in any rhetoric about repealing the Affordable Care Act," said Ron Pollack, president of Families USA.

And as the repeal debate subsides, Pollack sees room for compromise on healthcare issues such as extending the Children's Health Insurance Program. He's also hopeful Republicans might agree to add some health services to the list of things insurers must cover pre-deductible.

"Republicans would be resistant with respect to putting more money into how the ACA works, but that doesn't mean there can't be some incremental improvement," Pollack said. "Hillary is clearly going to be pushing the affordability agenda."

Topher Spiro, vice president for health policy at the Center for American Progress, said he wants to see insurance subsidies expanded under a Clinton White House, especially for middle-income Americans who aren't currently eligible for them. But regardless of what's possible politically, he wants to see the next president try to address the underlying cost of healthcare — and keep implementing the healthcare law.

"I think the key for the next administration is to really continue and double-down," Spiro said.