WASHINGTON (AP) -- There's a mixed message for the 50 million uninsured Americans in last week's Supreme Court health care ruling.

The justices upheld one mandate that affects the uninsured while potentially weakening another one that's just as vital.

The court approved the law's controversial requirement that nearly every U.S. resident carry health insurance or pay a fine. Experts say that's essential for guaranteeing affordable coverage in new private insurance markets for middle-class people and small businesses.

But the justices also gave states more leeway to opt out of the law's expansion of Medicaid, the federal-state program for low-income and disabled people.

About half the 30 million uninsured people who are expected to gain coverage through the law would do so through Medicaid. So that could be a problem.