The meeting last month was a watershed: the leaders of 564 American Indian tribes were invited to Washington to talk with cabinet members and President Obama, who called it “the largest and most widely attended gathering of tribal leaders in our history.”

Topping the list of their needs was better health care.

“Native Americans die of illnesses like tuberculosis, alcoholism, diabetes, pneumonia and influenza at far higher rates,” Mr. Obama said. “We’re going to have to do more to address disparities in health care delivery.”

The health care overhaul now being debated in Congress appears poised to bring the most significant improvements to the Indian health system in decades. After months of negotiations, provisions under consideration could, over time, direct streams of money to the Indian health care system and give Indians more treatment options.

Some proposals, like exempting Indians from penalties for not obtaining insurance, may meet resistance from lawmakers opposed to expanding benefits for Indians, many of whom receive free medical care.