One health policy professor said cutting Medicaid and similar programs "will be devastating" to millions of Americans.

Of the $16.4 billion annual Medicaid costs for Louisiana, state taxpayers kick in about $3 billion, according to the Legislature. The new law would halt some of the tools Louisiana uses to pay that $3 billion, requiring the state to pour in extra money or let some people go without health insurance.

The Congressional Budget Office estimates the Medicaid cuts could leave nearly 12 million Americans uninsured.