The Federated Indians of Graton Rancheria's constitution, and recent changes made to it, are a partial map to how the tribe has evolved as a body politic since 2000, when it had 400 members and had just won federal recognition.

The tribe now has about 1,300 citizens and is on the doorstep of potentially great wealth, with its 3,000-slot machine casino set to open this year.

And in its new constitution, which the federal government approved in January, the tribe takes steps that are likely to sharply limit its future growth.

Also evident in the constitution is that from the start the tribe has anchored considerable authority in its General Council, made up of all its adult members -- just under 800 people -- as opposed to its seven-member Tribal Council.

The tribe also has laid the groundwork for a legal system that includes a net of civil rights protections for its members as well as methods to resolve disputes.

Indian-law experts outside the tribe say the constitution shows it is maturing as a political entity.

"It's a very modern, sophisticated document that reflects what the tribal leadership and their lawyers have learned" since the tribe was restored by an act of Congress in 2000, said George Forman, an Indian-law attorney based in San Rafael.

The tribe first adopted its constitution in 2002. This January, it adopted a revised version that included key changes to the section governing who can become a citizen.

Those changes were made largely because the tribe's casino project -- and the income it promises tribal members -- has caused applications for citizenship to mushroom, said Graton Rancheria Chairman Greg Sarris.

"We are being bombarded," he said this week.

To address that, proof of biological lineage is required of all people who want to enroll as citizens, and anyone claiming descent through their father must take a DNA test.

That's a necessary safeguard, said Sarris, who has himself faced allegations that he is not Indian, most recently from a cousin.

"We had instances where women were coming and claiming their children were from Indian guys and in fact they weren't," Sarris said. "We had instances where the actual father said, 'Hey, that's my kid.' "

However, if the mother is an enrolled member, no blood testing is mandated.

In other areas, the constitution stands out, experts say, in that it establishes that the General Council, not the Tribal Council alone, has the authority to waive the tribe's sovereign immunity.

Such a waiver means the tribe relinquishes the immunity to being sued that it is granted as a government, a protection similar to that enjoyed by the federal and state governments.

The tribe waived immunity, for example, in revenue-sharing deals it signed with Sonoma County and Rohnert Park, and in the 2012 agreement with the state that allows it to run a Las Vegas-style casino.

"It's pretty rare to see that as an expressed general council power," said Scott Wheat, who has worked as a tribal court judge and is an attorney with Crowell Law Office-Tribal Advocacy Group in Spokane, Wash.

"They are wise, in my view, to make it real clear . . . that they (the General Council) jealously guard that immunity," he said.

Also, the constitution from the start included standard language that affirms tribal members are protected by the 1968 Indian Civil Rights Act -- which made tribes subject to most of the U.S. Bill of Rights, and gave federal courts the ability to intervene in tribal matters if those rights were violated.

But the revised constitution spells out explicitly that tribal citizens who feel their rights have been stepped on can seek a remedy either in a tribal court -- which has not been established yet -- or some other method of alternative dispute resolution.

"Putting these in there means they're hopefully going to ensure due process and equal protection to their members," said Paula Fisher, a Santa Rosa tribal law attorney who specializes in membership issues.

"It appears they're going to do that," she said, adding, "If you fine-tune the front end, you don't have problems in the back end, and that's what it looks like they're doing."

You can reach Staff Writer Jeremy Hay at 521-5212 or jeremy.hay@pressdemocrat.com.