Washington (CNN) -- President Barack Obama on Thursday signed the Tribal Law and Order Act, which provides greater law enforcement powers for tribal authorities on Indian reservations.
At an emotional White House ceremony, Obama comforted a rape victim who broke down while trying to introduce him, by coming out early and offering her reassurance as she struggled to tell her story.
Lisa Marie Iyotte of the Rosebud Sioux Tribe wept openly in describing the assault in 1994 by an attacker who was later convicted of another rape, but never prosecuted for the crime against Iyotte.
Obama said the law he was signing would help prevent something like that from happening.
Crime rates on some Indian reservations are 20 times higher than the national average, Obama said, adding that one in three Native American women are raped in their lifetimes, which he called "an assault on our national conscience."
"These are significant measures that will empower tribal nations and make a real difference in people's lives," Obama said of the new law.
The law requires the Department of Justice to improve coordination with tribal justice officials in prosecuting crimes on reservations, and provides resources for better overall cooperation between tribal, state and federal agencies.
In addition, the measure increases the maximum sentence that tribal courts can impose to three years, instead of the previous limit of a one-year sentence. Supporters of the measure say the sentencing provision will expand the number of cases handled by tribal courts, increasing local tribal control on reservations.
The new law reauthorizes existing initiatives such as at-risk youth programs and treatment programs, said Jefferson Keel, president of the National Congress of American Indians.
"Law enforcement on tribal lands has long been hamstrung by a lack of resources and by restrictions placed by the federal government," Keel said. "The Tribal Law and Order Act is a significant step forward for tribal police."
The House approved the bill last week; it passed the Senate in June.