Endangered Republican candidates are fighting back against the narrative being advanced by Democrats that they are the villains in the battle over who would better manage the nation’s health-care system and protect those Americans with preexisting conditions.

They are doing so by releasing personal campaign ads in which they share their own health stories such as a child’s illness like leukemia -- and by suddenly introducing bills in Congress to require that people with prior coverage don’t lose access to affordable health care.

It’s a significant twist in the way candidates are talking about health care on the campaign trail less than a month before voters head to the polls. Democrats believe health care will be a major factor in which party controls Congress come January and have leaned heavily on the issue. Polling shows that health care is a top priority for many Americans, and that Democrats are winning among the segment of the electorate most worried about it.

Rodney Whitlock, a health-policy expert who worked for Republicans in Congress, said Democrats have the upper hand in this fight. No matter what Republicans propose, he said, Democrats will argue it pales compared to the protections afforded by the Affordable Care Act.

At the end of the day, he said, "as with so much in politics, if I make an attack and you have to defend against it, I’m winning.”

In 2018, Republicans have found themselves on the defensive when it comes to an issue they used to champion -- eliminating President Obama’s signature domestic achievement. An intra-party feud over doing so resulted in legislation that couldn’t get through the Senate last summer, as Democrats and grassroots advocates built a case that the GOP effort to repeal and replace Obamacare would leave millions without coverage and weaken preexisting condition protections.

The Democrats' argument was bolstered when the Trump administration announced it would not defend the ACA against a lawsuit brought by 20 GOP-led states claiming Obamacare should be struck down in its entirety because Republicans removed a key piece of it. If successful, Democrats warned, even the popular provisions of the ACA, like preexisting condition protections, would be eliminated.

The Trump administration has also steadily chipped away at some of Obamacare’s key components -- the GOP Congress eliminated the individual mandate penalty last year; and the administration is allowing some states to require Medicaid recipients to work, as well as permitting people to buy skimpier heath plans.

Nonetheless, President Trump is vowing that he will protect access to care for those with health problems.

“We will always protect Americans with preexisting conditions. We are going to protect Americans with preexisting conditions,” Trump said at a rally in Council Bluffs, Iowa, on Tuesday evening. He made the same pledge in a USA Today op-ed published Wednesday morning.

Republicans almost unanimously opposed a plan forced to the Senate floor by Democrats on Wednesday to stop the administration from expanding short-term insurance plans, which offer far fewer benefits and aren’t required to cover people with preexisting conditions. Sen. Susan Collins (Maine) was the only Republican to side with Democrats.

“What just happened in the Senate revealed Republicans’ dishonesty regarding what it takes to protect against discrimination based on health status,” said Judy Feder, a professor of public policy at Georgetown University and former Clinton administration official. “I would argue they are disingenuous or ignorant of what it takes to get decent health coverage regardless of health status.”

The issue came up at two Senate debates this week.

Mike Braun, who is running neck-in-neck with incumbent Democratic Sen. Joe Donnelly in Indiana, said during their debate on Monday that he “would never be for any replacement of the Affordable Care Act unless it covered preexisting conditions.”

And Leah Vukmir, who is running to unseat incumbent Democratic Sen. Tammy Baldwin in Wisconsin, said during a debate, also on Monday, that she would “fall in front of a truck before I would let people go without coverage for preexisting conditions.”

Yet, both candidates are on the record as being supportive of past GOP efforts to roll back Obamacare.

The House and Senate bills to repeal and replace the ACA — the former passed the lower chamber and the latter failed the upper one by one vote — were both criticized for rolling back key elements that would have resulted in millions of people losing coverage and weaker protections for those with illnesses.

“Republicans are running really scared on this issue,” said Brad Woodhouse, of Protect Our Care, a left-leaning coalition advocating for the ACA. “I think what they are doing reeks of desperation. They are obviously trying to muddy the water.”

In Washington, vulnerable Republicans have suddenly introduced a slew of bills they say would protect those with preexisting conditions. But the legislation seems less intended as an actual policy solution than armor against Democratic attacks. And their vague approach to the issue raises eyebrows among health-policy experts because the bills leave loopholes that would allow insurers to limit coverage.

In August, ten Senate Republicans, including Sen. Dean Heller of Nevada, one of the most vulnerable GOP senators facing a reelection challenge next month, sponsored a bill to guarantee protections for patients with preexisting conditions in the event that the ACA is struck down by the courts.

While the bill, led by Sen. Thom Tillis (R-N.C.), forces insurers to sell plans to individuals with certain conditions, the insurers could exclude coverage for services associated with those conditions. For example, a person with cancer couldn’t be denied coverage, but the insurer wouldn’t be required to cover that patient’s cancer treatments.

Tillis’s spokesman, Daniel Keylin, said the bill wasn’t meant to be “comprehensive health care legislation,” or the “totality of Congress’ answer to the Affordable Care Act falling.”

“There is obviously no ironclad way to precisely predict how the court will rule, however this legislation is an important preemptive step toward getting feedback, hashing out ideas, and underscoring the importance of protecting Americans with preexisting conditions," Keylin said.

Meanwhile, on the House side, Rep. Steve Knight (R-Calif.), who is fending off a difficult challenge in California’s 25th District, introduced a bill in September similar to Tillis’s proposal. And two other Republican congressmen locked in tight races recently introduced nonbinding resolutions addressing preexisting conditions, though both are even more vague on details.

Iowa Republican Rep. David Young’s resolution says regardless of what happens to the ACA, Congress should retain preexisting condition protections, whereas Texas Republican Rep. Pete Sessions’s version says states should be allowed to reform their individual health-care marketplaces, but should ensure people with preexisting conditions still have access to affordable coverage.

But Joseph Antos, an expert in health care at the conservative American Enterprise Institute, isn’t convinced the House bills, or the Senate Democrats' vote on the short-term plans, will resonate with voters.

“The whole purpose is so a few House Republicans can say to their constituents we voted to protect you,” he said. " This attempt (by Democrats) to force a vote is a similarly meaningless gesture. These frankly subtle arguments are going to fly under the toes or over the head of virtually anyone."

But Democrats have made the issue personal by settling on something nearly every American can relate to by airing campaign ads featuring stories of constituents with illnesses and by asking voters at events to raise their hands if they have a preexisting condition. They have also spoken candidly about their own experiences.

So, in the waning weeks of the campaign, Republicans are trying to make health care personal, too.

Last week, Rep. Dana Rohrabacher (R-Calif.) released a digital ad talking about his daughter’s diagnosis of leukemia when she was eight years old. In the ad, he says, he is “taking on both parties, and fighting for those with preexisting conditions.”

And earlier last month, Missouri Attorney General Josh Hawley, who is in a razor-thin contest against incumbent Sen. Claire McCaskill (D-Mo.), put out a TV ad discussing his son’s rare chronic disease. In it, he looks at the camera and says, "I support forcing insurance companies to cover all preexisting conditions.”

But Democrats are quick to point out that Hawley is one of the 20 attorneys general and governors who filed the lawsuit against the ACA that would result in ending protections for preexisting conditions.