Probably the most obvious wedge is protection for people with pre-existing conditions. Before ObamaCare was passed, it was generally legal for insurance companies to deny coverage for people with illnesses or conditions that might prove expensive to treat, if they had not maintained previous coverage.
One of the ObamaCare regulations was a ban on that kind of discrimination, and it is enormously popular. Fully 64 percent of Americans oppose repealing that ban — 70 percent of Democrats and 71 percent of independents, but also 49 percent of Republicans. Just 36 percent of Republicans support repealing that ban and returning to the pre-2010 status quo.
This issue is especially strong because it has been extensively discussed, and many if not most people personally know someone who has a pre-existing condition. One of those people is Sen. Claire McCaskill (D-Mo.) herself, who got breast cancer two years ago and is in a tough re-election race. Her Republican opponent, Missouri Attorney General Josh Hawley, has signed his state up with the latest conservative judicial activism lawsuit trying to repeal ObamaCare through Federalist Society argle-bargle.