SAN FRANCISCO — When Liz DeRouen needs any kind of health care services, from diabetes counseling to a dental cleaning, she checks into a government-funded clinic in Northern California's wine country that covers all her medical needs.

Her care and the medical services for her children and grandchildren are paid for as part of the government's treaty obligations to American Indian tribes dating back nearly a century. But under President Barack Obama's health care overhaul, DeRouen and tens of thousands of others who identify as Native American will face a new reality.

They will have to buy their own health insurance policies or pay a $695 fine from the Internal Revenue Service unless they can prove that they are "Indian enough" to claim one of the few exemptions allowed under the Affordable Care Act's mandate that all Americans carry insurance.