Obamacare, President Donald Trump is fond of saying, is a "complete and total disaster" and must be replaced. Yet one of the most significant features of his party's proposed replacement has little to do with Obamacare.

The American Health Care Act would drastically reshape Medicaid — ending the federal government's long-running, open-ended commitment to help states pay for care for the poor. Instead, in 2020, Washington would make limited per capita contributions that would shrink as a share of costs with every passing year.

True, expanded eligibility for Medicaid is an important part of Obamacare. And the AHCA would reverse this expansion. But its much bigger change is to the Medicaid program as it existed long before Obamacare. Medicaid is a popular and relatively efficient insurance program that has provided health care and peace of mind for millions of Americans for more than half a century. Why start taking it apart now?