As lawmakers’ debate over Affordable Care Act enhanced premium subsidies continues, Republicans have pointed to reports of fraud in the health insurance marketplace as a reason they shouldn’t extend the tax break.

GOP lawmakers cited a Dec. 3 report from the U.S. Government Accountability Office, a nonpartisan congressional watchdog, on fraud tied to ACA subsidies.

Democrats’ proposal to extend the ACA enhanced credits “is rampant — and I say rampant — with fraud and abuse,” Senate Majority Leader John Thune, R-SD, said on the Senate floor Thursday.

Some health policy experts say the scope of the fraud isn’t as severe as lawmakers have suggested, and that it’d be better to improve Obamacare’s security measures rather than cut enhanced subsidies altogether.

“It really is trivial, the scope of fraud,” said Michael Gusmano, a professor of health policy at Lehigh University. “It’s just a scare tactic to justify the reduction of the federal government’s role in subsidizing health insurance,” he said.