Candidates in a critical Kentucky race that could flip control of the House sparred over healthcare Monday night, with Republican Rep. Andy Barr accusing his Democratic challenger Amy McGrath of supporting socialized medicine and McGrath calling the incumbent a liar.

Barr, who is facing his first real challenge this cycle, has tried to label McGrath as being on the “extreme far Left” on healthcare, defending against attacks that he voted for the House Republican plan to repeal the Affordable Care Act.

“How can you continue to lie?” McGrath challenged Barr as he accused her of supporting single-payer healthcare, which has become a rallying cry for progressives in other parts of the country.

McGrath backs a public option that would compete with private plans and she supports protecting pre-existing conditions. In the final days of the campaign McGrath, like many Democratic candidates running to pick up red seats, has tried to keep the focus on healthcare.

When pressed on his vote to repeal the ACA and comments by Senate Majority Leader Mitch McConnell, R-Ky., that Republicans could again try to repeal the law, Barr said he wants to “replace it.”

“I certainly don’t want to just repeal the law and go back to the status quo,” he said.

As for protecting people with pre-existing conditions, Barr claimed that Republicans have “always been” for protecting pre-existing conditions. “We’ve always been,” he said.

Barr voted repeatedly to repeal the ACA, and the Trump administration supports a lawsuit that would declare the law unconstitutional, gutting protections for pre-existing conditions.

“I would not vote for legislation that would not fully protect people with pre-existing conditions,” Barr told reporters after the debate.

The bill Barr supported dubbed the American Health Care Act, which passed the House but not the Senate, would have scrapped premium limits for those with pre-existing conditions established under the ACA and an analysis conducted by the nonpartisan Kaiser Family Foundation said more than 6 million people who would be considered to have a pre-existing condition would have faced higher premiums and surcharges.

Pressed on whether the Trump administration should drop its lawsuit arguing that protections for people with pre-existing conditions are unconstitutional under the ACA, Barr pointed to his vote for the Republican AHCA plan and said he needed to “familiarize” himself with the lawsuit.

“I’m not going to necessarily agree with the premise of your question, I’d like to familiarize myself with the lawsuit itself,” Barr said.