Those reforms were a success. They led to increased work and earnings among low-income families, along with record declines in poverty and dependence on government benefits. States were given fixed federal funding and flexibility in designing welfare programs in exchange for a simple promise: that they would engage welfare recipients in work and related activities.

Here are just a few of the specific results of welfare reform. Employment of single mothers increased by 15 percent from 1996 through 2000, and even after the recession, the proportion is still higher than before welfare reform. According to the Department of Health and Human Services’ latest report on the welfare program, “earnings in female-headed families remained higher in 2009 than in 1996 despite various shifts in the economic climate since [the law’s] enactment.”

Welfare reform replaced the New Deal-era Aid to Families With Dependent Children in 1996, and since then, the reforms have cut welfare dependence. Caseloads declined by 57 percent through December 2011. Child poverty in female-headed households fell dramatically after welfare reform and is still down more than 15 percent below the level of the early 1990s.

Yet the president would eliminate the critical work requirements that led to these improvements by letting states opt out for the first time. After 16 years of success, Mr. Obama is turning back the clock on bipartisan reforms and returning welfare to a system of check-writing and dependency instead of one focused on helping Americans find and maintain jobs.

Not only is this bad policy, the president is breaking the law in his attempt to undermine welfare reform. He is trying to exercise authority he doesn’t have. When Mr. Clinton signed the welfare reform bill into law, it contained specific language prohibiting any administration from granting states waivers from the work requirement.

It is one thing for the administration to push policies that haven’t improved the economy and won’t help the unemployed find work; the failed stimulus and Obamacare policies fall into that category. It is an entirely different matter to seek to undo welfare reforms that successfully increased employment and earnings for low-income Americans. That’s what this latest “waiver” plan from the Obama administration amounts to — “waiving” what has worked to help low-income parents find jobs instead of spending year after year on welfare.

Despite requests from congressional Republicans, the Obama administration so has far refused to adhere to the law and bury its waiver proposal. That’s why Sen. Orrin G. Hatch of Utah and I introduced legislation to block the administration from weakening the work requirements. If the administration doesn’t withdraw its misguided plan, Congress can and should make sure work requirements remain a key component of welfare programs.

It shouldn’t have to come to that. Mr. Obama has the opportunity to follow the law and support bipartisan welfare reform. He should stop this attack on the work requirement, which has helped lift families and children out of poverty.

Rep. Dave Camp, Michigan Republican, is chairman of the House Ways and Means Committee.