Oklahoma declined to set up an insurance exchange or to expand its Medicaid program, which has some of the nation’s most restrictive eligibility criteria. State officials say the number of private insurers participating on the federal insurance exchange here has fallen, and the premiums of the insurance plans on offer have increased.

The public’s attitude can also be an obstacle: Supporters of the Affordable Care Act often encounter stony skepticism here.

“‘Obamacare’ is a cuss word in this state,” said former Gov. David Walters, a Democrat.