The insurance industry, concerned that it will be left operating in an unsustainable market, has been particularly exercised in emphasizing this point at every turn. On Tuesday, it sent a letter to congressional leaders urging them to preserve the mandate.

For years, conservative health care analysts have said the budget office has erred in assuming that the insurance requirement has so much power over who gets health insurance. Under the budget office’s estimates, eliminating the mandate doesn’t just drive people out of the individual insurance market, where people pay premiums to buy coverage; it also sharply lowers the number of people enrolled in Medicaid, a program that low-income Americans can access largely without cost to them. Republican critics have said that the Medicaid estimates are unrealistic and unfair to any health reform plan that doesn’t include a mandate.

But now Republicans are embracing what they have long described as the mandate’s overstated importance. That’s because the only way the measure could achieve $338 billion in savings is by causing many fewer Americans to have government-subsidized health insurance. Most of the savings in the budget office’s calculations regarding repealing the mandate come from lowering Medicaid enrollment. If the budget office took the Republican critiques to heart, the mandate would be much less useful as a component of tax reform.

And it appears the budget office has, indeed, heard their complaints. In the recent report, its economists indicated that the office was re-evaluating its assessment of the mandate.

“The agencies have undertaken considerable work to revise their methods to estimate the effects of repealing the individual mandate,” the report notes near its end. While that work was not completed in time to assess the current tax proposal, new estimates should be ready soon. Under the new model, “the estimated effects on the budget and health insurance coverage would probably be smaller than the numbers reported in this document,” the report says.

That will make the mandate less central to the success of future health care overhaul ideas. And less valuable as a means to pay for tax cuts.

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