"The top three issues this year are health care, health care, health care," said J.B. Poersch, the head of Senate Majority PAC, the super PAC closely tied with Senate leadership.

In Arkansas, congressional candidate Clarke Tucker ran an ad in April that addressed his own cancer diagnosis and pledged to "stand up to anyone who tries to take your health insurance."

"It just gives you a new perspective on life, on what is important and what is not important," Tucker told CNN about his diagnosis. "It made me recognize that without health you can't really do anything else."

Cindy Axne, running to represent Iowa's 3rd Congressional District, has told audience about how she and her husband were "had to sell our personal items on eBay because we couldn't get affordable maternity care" when they had their second child.

"Sadly," she said in a recent interview, "my story isn't unique."

Democrat Josh Harder, who is challenging Rep. Jeff Denham in California's Central Valley, has framed his family's health care story as a catalyst for his congressional bid. Harder's brother was born premature, racking up a $2 million hospital bill that was mostly covered by his family's insurance plan.

"When our congressman Jeff Denham voted to take health insurance away from 100,000 people in this district and eliminate protections for preexisting conditions like my brother's," Harder said in one campaign ad, "it's not just wrong, it's personal."

And Sens. Claire McCaskill and Heidi Heitkamp, two vulnerable Democratic senators running for reelection in Missouri and North Dakota, unveiled ad this year about beating breast cancer during their career.

"Two years ago, I beat breast cancer," McCaskill said in the ad. "Like thousands of other women in Missouri, I don't talk about it much."

While different topics have dominated the national conversation, Democrats have remained committed to health care messaging all cycle. In total, Democratic candidates in 2018 have spent over $184 million on health care ads, a figure that dwarfs the roughly $52 million they have spent on anti-Trump spots, the second most prevalent topic for Democrats.

For Republicans, health care at $73 million is the second most discussed topic in television ads behind around $100 million in pro-tax reform spots.

Over 50% of all Democratic ads run in 2018 have been on health care, according to data collected by CMAG/Kantar Media. That number is only 22% for Republicans.

Polls have shown that the Democratic health care message has resonated with voters and left Republicans on the defensive with an issue that they once dominated.

"We weren't prepared for an issue that was extremely positive for us in 2016 to become an extreme negative," said one Republican campaign operative.

"It's a place where Republicans have typically struggled," said Doug Heye, a Republican strategist and CNN contributor. "Republicans tend to be more comfortable talking about budget outlays than demonstrating that they care about people and what they go through."

Some Republican candidates have begun airing personal health care stories of their own.

Republican Rep. Dana Rohrabacher has begun airing an ad where he stands beside his wife and daughter, Annika, who survived leukemia.

"Politicians argue a lot about health care," says Rohrabacher, who is in a competitive race in Southern California. "But for me, it's personal,"

A recent ad from Republican gubernatorial candidate Mike DeWine in Ohio is narrated by his daughter, Anna, who describes how her sister Becky's death shaped DeWine's approach to health insurance and prescription drug pricing.

"Family is at the core of everything Mike DeWine does," Anna says. "That's why he's always protected Ohio's families."

And Missouri Attorney General Josh Hawley, the Republican Senate candidate who has come under attack by McCaskill on preexisting conditions, cut an ad featuring his oldest son, who has a preexisting condition.

"I support forcing insurance companies to cover all pre-existing conditions, and Claire McCaskill knows it," Hawley says in the ad. "You deserve a senator who's driven to fix this mess. Not one just trying to hang on to her office."

To some degree, Republicans have become victims of their own success on health care. Republicans for years voted for repealing the Affordable Care Act with few repercussions given the fact that Democrats controlled the White House and would happily veto any plan that took a bite out of the ACA. With Trump in the White House, though, Republicans are now forced to back up their anti-Obamacare messaging with results, making their plan to repeal a bill that is growing in popularity more politically perilous.

One way to cut against that is by making the issue personal as a way to convince voters that a candidate understands their struggles and concerns, Republican strategists said.

Brad Todd, a Republican consultant advising Hawley's campaign, said the ad's emotional, personal approach was "the clearest way to tell the story."

"All politics," said Todd, "is personal."