“Mend it, don’t end it” was Bill Clinton’s rhetorical straddle regarding affirmative action. Republican efforts to “repeal and replace” the Affordable Care Act (Obamacare) look increasingly like “mend it, don’t end it.”

The problem is not that, as is frequently said, no entitlement can be ended. The most consequential legislation of the 1990s, the 1996 welfare reform, repealed a portion of the 1935 Social Security Act, which, through Aid to Families with Dependent Children, conferred a lifetime entitlement to welfare. Perhaps entitlements for the middle class are immortal. We shall see, as Social Security and Medicare as currently configured approach insolvency.

Meanwhile, Republicans who repeatedly voted to repeal the ACA — before voters gave them congressional majorities and a president who would sign a repeal — now must replace it. They must do so in conditions that have changed since, and partly because of, the ACA.

It is unknowable whether Barack Obama produced an American consensus in favor of a government obligation to guarantee universal access to health insurance, or whether the debate surrounding the ACA merely catalyzed a gradually forming consensus. In any case, today’s debate about replacing the ACA is occurring in the context of that consensus. And in the context of several other new beliefs: Health insurance should not be denied because of an applicant’s pre-existing medical conditions. And federal law should provide a refundable tax credit entitlement, and require that children up to age 26 be eligible for coverage under their parents’ insurance.

Furthermore, Republicans are insufficiently radical as they largely accept this third-party payer system that distorts decisions about recourse to the health care system: Upward of 180 million Americans are covered by employer-provided insurance, which is not taxed as what it obviously is — compensation. Republicans have abandoned a measure to treat as taxable income a small portion of the most generous employer-provided insurance plans, and have postponed for nearly a decade — meaning, probably, forever — the “Cadillac tax” on such plans.

Given all this, it is probable that whatever replaces the ACA’s tapestry of subsidies, regulations and mandates will be a tapestry of subsidies, regulations and mandates. The differences probably will constitute substantial improvements but will hardly constitute a revolution in the relation of the citizen, or the health care sector, to the government.

Today, this sector is one-sixth of the American economy and larger than all but four national economies. It has been observed that if in 1900 America had had sophisticated national income statistics, the health care sector would have been too negligible to notice: Most Americans then were born and died at home and rudimentary medicine was mostly for making sick persons as comfortable as possible while nature healed or killed them.

As a subject of political contention, medicine’s importance has risen rapidly with its competence. In 1900, 37 percent of American deaths were from infectious diseases; today 2 percent are. Medicine has advanced from the conquest of infectious diseases to the management of chronic ailments. And to the center of American politics.

Legislative bargaining often is additive: Supporters of legislation A endorse legislation B so that its advocates will reciprocate by supporting A. By this process a coalition (and government) grows. However, congressional bargaining about replacing/mending the ACA might become an exercise in subtraction. The debate is making clear that the expansion of a 52-year-old program, Medicaid, is the most important aspect of the 7-year-old ACA. Twenty Republican senators represent states that expanded Medicaid and face budget agonies if the expansion is abruptly reversed. But many Republican representatives and senators believe it should be. Perhaps this is a difference that can be split. If not, adding the support of some legislators will subtract that of others.

A religious skeptic in 19th-century England proposed carving three words over the portals of all the nation’s churches: “Important if true.” These words should be affixed to the Congressional Budget Office’s projections about how many more people will be uninsured in 2026 under Speaker Paul Ryan’s replacement proposal (24 million) and the effect of it on the deficit (a $337 billion reduction over 10 years).

Conservatives warn against the fatal conceit of thinking that one can predict the consequences of comprehensive government interventions in complex systems. Now many Republicans say they know the CBO is wrong, and that they can structure incentives to accomplish more skillfully, and with less comprehensive health care planning, what the ACA attempted. This confidence is important, whether or not it is true.

© 2017, Washington Post Writers Group