President Barack Obama’s signature achievement, the 2010 expansion of health insurance known as Obamacare, has proved successful and popular. More than 45 million Americans have health insurance today as a direct result of the legislation. And most Republican politicians have stopped openly campaigning to kill the program.

But make no mistake: The big domestic policy bill that Republicans are trying to push through Congress is an effort to reverse the progress of the past 15 years. Despite their claims of having become a working-class party, Republicans are seeking to take away health insurance from millions of Americans, and they are doing it to give billions of dollars in tax cuts to the wealthy.

The most important attempt to undermine Obamacare is also the most cleverly disguised. To restrict access to Medicaid — the federal program that Obamacare expanded and that covers medical costs for lower-income people, including children, the elderly and people with disabilities — House Republicans are proposing to add a work requirement to the program. The proposal would strip Medicaid benefits from working-age adults who do not have children unless they can prove they are working at least 80 hours a month. That would result in 7.7 million Americans losing health insurance by 2034, according to the Congressional Budget Office.

Proponents describe it as a common-sense measure to encourage work and prevent mooching off the government. They insist it is substantively different from cutting Medicaid funding. Senator Josh Hawley of Missouri, for example, has described outright cuts as “morally wrong and politically suicidal,” but he says that he is in favor of work requirements.

We are sympathetic to the idea that some government benefits should be tied to employment. People benefit from working, and society benefits when more people are working. But health care is the wrong target. All Americans deserve access to affordable health care. Every other developed nation already ensures universal access, and the expansion of Medicaid under Obamacare, while flawed and inefficient, has brought the United States closer to that goal. Republicans are not proposing to fix the flaws. They are not proposing to deliver better health care at a lower cost. The bill would save money by depriving Americans of health insurance.

Furthermore, the evidence suggests that work requirements don’t work. Federal law already allows states to impose Medicaid work requirements in some situations, and Arkansas briefly did during the first Trump administration. Subsequent studies found no resulting increase in work force participation. Most of those subject to the work requirements already were working, and the termination of benefits did not address the reasons the remainder were not.