A Democratic congressman said that Republicans aren’t offering a unique alternative to Obamacare because they know that the only working substitute would be Medicare-for-all.

Rep. John Yarmuth (D-Ky.) made the accusations on Wednesday, at a House committee hearing set up by Republicans to criticize the Affordable Care Act (ACA).

“The reason they have not proposed a viable alternative to the ACA, other than going back to pre-ACA situation, I’m convinced, is because the only other alternative is single-payer,” Yarmuth said.

The law has come under scrutiny in recent weeks, after Aetna withdrew plans from 11 state health insurance exchanges set up under the law.

The company, in turn, came under fire, after it was revealed that Aetna executives first threatened to walk away from exchanges, if its merger with Humana was rejected by the Justice Department Antitrust Division.

But those problems and most other concerns about the quality and cost of health insurance under Obamacare would disappear, Yarmuth said, if we would just listen to Sen. Bernie Sanders (I-Vt.)

“If you listen to virtually every complaint that’s raised during this hearing today and in every other hearing: those complaints would not exist under a single-payer system,” Yarmuth said.

“I don’t think anybody’s ready to go there right now,” he added. “We’re gonna end up there eventually.”

Sanders’ presidential campaign enjoyed once-surprising amounts of support during the Democratic primary, buoyed, in part, by calls to establish a single payer system.

The eventual Democratic nominee, Hillary Clinton, harshly criticized the idea in January, saying that single-payer “will never, ever come to pass.”

“I don’t want it repealed,” she said of the ACA. “I don’t want us to be thrown back into a terrible, terrible national debate. I don’t want us to end up in gridlock. People can’t wait.”