The Congressional Budget Office's updated score for the Patient Protection and Affordable Care Act now projects that the law will cover 3 million few individuals and cost $84 million less than previously estimated. The update, released this afternoon, comes in the wake of the Supreme Court's ruling that states can opt out of Medicaid without risking existing federal Medicaid matching funds. The CBO expects that as a result of that ruling, some states will choose not to expand Medicaid, which will mean fewer Medicaid enrollees, but somewhat more enrollees in subsidized private coverage through the law's health exchanges.
CBO and JCT [Joint Committee on Taxation] now estimate that fewer people will be covered by the Medicaid program, more people will obtain health insurance through the newly established exchanges, and more people will be uninsured. The magnitude of those changes varies from year to year.
In 2022, for example, Medicaid and the Children’s Health Insurance Program (CHIP) are expected to cover about 6 million fewer people than previously estimated, about 3 million more people will be enrolled in exchanges, and about 3 million more people will be uninsured.
On cost, the CBO says:
CBO and JCT now estimate that the insurance coverage provisions of the ACA will have a net cost of $1,168 billion over the 2012–2022 period—compared with $1,252 billion projected in March 2012 for that 11-year period—for a net reduction of $84 billion.
This is an estimate of the law's total cost, not its effect on the budget deficit. The CBO still projects that the law will reduce the deficit. Expect the law's backers to point this out, but not to note that the projection still has the same potential for error as it's always had. If everything goes exactly as planned, the law will reduce the deficit, all else being equal. But that's not likely. The deficit score relies on legislative reality, but not political reality.