In years past, Obamacare was the stuff of Republican attack ads. No more.

This cycle, even Democrats running in red states are unapologetically putting health care at the center of their campaign messages. There’s a reason: Republican efforts to overhaul the health care system last year were deeply unpopular.

A lawsuit brought by several states imperils the health law’s protections for people with pre-existing health conditions, the law’s most popular provision. Recent polls show growing numbers of Americans rank health care as a top issue, and coverage for pre-existing conditions as an important policy.

A recent analysis from the Wesleyan Media Project showed that health care was the most common subject of televised campaign advertisements by Democrats in both the House and the Senate. “This is the uniform issue across a lot of the states, and then these candidates will talk about things that are particular to their constituents,” said Lauren Passalacqua, the communications director for the Democratic Senatorial Campaign Committee.

Some ads focus on a personal connection to the issue, like the health history of a candidate or a candidate’s relative. Some focus on an opponent’s role in the lawsuit. Many House campaigns are using health care as part of attack ads against Republican incumbents who voted last year for the American Health Care Act, which would have unwound major parts of the Affordable Care Act. Some ads talk about the Affordable Care Act directly, but many gesture at it more obliquely, with talk of pre-existing conditions alone.