Before the ACA's guaranteed-issue rule, which banned insurers from discriminating against those with pre-existing conditions, many people struggled to obtain or afford insurance because of their medical history.
A Kaiser Health Tracking Poll from June 2013, months before the guaranteed-issue provision went into effect, found that 49% of adults said they or someone in their household had a pre-existing condition. One-quarter of those respondents reported being denied insurance or given a premium increase, and 9% said they had stayed at a job just for the health insurance.
An HHS analysis in 2012 similarly found that as many as half of the nation's adults had some type of pre-existing condition.
These ACA provisions, individually, are popular among Americans. Another Kaiser poll found 70% to 80% approval for the changes to preventive care, dependent extension, subsidies and guaranteed issue.
Katherine Hempstead, director of health insurance coverage for the Robert Wood Johnson Foundation, said the three key provisions of the ACA are the individual mandate, tax credits to help Americans buy insurance, and the ban on turning away those with pre-existing conditions.
The individual mandate may be controversial, but the other two provisions would be difficult to roll back. And all three are needed for the system to work, she said.
“Sometimes people talk about that as the three legs of the stool,” she said.
Getting rid of tax credits would be devastating for the individual market. Doctor who receive them are grateful to take them, but those who don't get tax credits also rely on the large risk pool for the market to function. And the markets are all connected, so those with employer-sponsored insurance would feel the effects as well, Hempstead said.
Coverage for pre-existing conditions has been a huge achievement and a cultural change that shows a shift in values. It would be surprising for any state to return to medical underwriting, she said.
All the Republican presidential candidates have said they would repeal and replace the ACA, but they have given few details about how they would replace it.
Donald Trump, who leads in delegates, released a seven-point plan relying heavily on allowing consumers to buy insurance across state lines and issuing health savings accounts. He has said in debates that he would make sure people with pre-existing conditions would be able to get coverage, but his plan does not mention it.