EMMONAK, Alaska >> She was 19, a young Alaska Native woman in this icebound fishing village of 800 in the Yukon River delta, when an intruder broke into her home and raped her. The man left. Shaking, the woman called the tribal police, a force of three. It was late at night. No one answered. She left a message on the department’s voice mail system. Her call was never returned. She was left to recover on her own.

“I drank a lot,” the woman said this spring, three years later. “You get to a certain point, it hits a wall.”

One in three American Indian women have been raped or have experienced an attempted rape, according to the Justice Department. Their rate of sexual assault is more than twice the national average. And no place, women’s advocates say, is more dangerous than Alaska’s isolated villages, where there are no roads in or out, and where people are further cut off by undependable telephone, electrical and Internet service.

The issue of sexual assaults on American Indian women has become one of the major sources of discord in the current debate between the White House and the House of Representatives over the latest reauthorization of the landmark Violence Against Women Act of 1994.

A Senate version, passed with broad bipartisan support, would grant new powers to tribal courts to prosecute non-Indians suspected of sexually assaulting their Indian spouses or domestic partners. But House Republicans, and some Senate Republicans, oppose the provision as a dangerous expansion of the tribal courts’ authority, and it was excluded from the version that the House passed last Wednesday. The House and Senate are seeking to negotiate a compromise.

Here in Emmonak, the overmatched police have failed to keep statistics related to rape. A national study mandated by Congress in 2004 to examine the extent of sexual violence on tribal lands remains unfinished because, the Justice Department says, the $2 million allocation is insufficient.

But according a survey by the Alaska Federation of Natives, the rate of sexual violence in rural villages like Emmonak is as much as 12 times the national rate. And interviews with Native American women here and across the nation’s tribal reservations suggest an even grimmer reality: They say few, if any, female relatives or close friends have escaped sexual violence.

“We should never have a woman come into the office saying, ‘I need to learn more about Plan B for when my daughter gets raped,”’ said Charon Asetoyer, a women’s health advocate on the Yankton Sioux Reservation in South Dakota, referring to the morning-after pill. “That’s what’s so frightening — that it’s more expected than unexpected. It has become a norm for young women.”

The difficulties facing American Indian women who have been raped are myriad, and include a shortage of sexual assault kits at Indian Health Service hospitals, where there is also a lack of access to birth control and sexually transmitted disease testing. There are also too few nurses trained to perform rape examinations, which are generally necessary to bring cases to trial.

Women say the tribal police often discourage them from reporting sexual assaults, and Indian Health Service hospitals complain they lack cameras to document injuries.

Police and prosecutors, overwhelmed by the crime that buffets most reservations, acknowledge that they are often able to offer only tepid responses to what tribal leaders say has become a crisis.

Reasons for the high rate of sexual assaults among American Indians are poorly understood, but explanations include a breakdown in the family structure, a lack of open discussion about sexual violence and alcohol abuse.

Rape, according to Indian women, has been distressingly common for generations, and they say tribal officials and the federal and state authorities have done little to help halt it, leading to its being significantly underreported.

In the Navajo Nation, which encompasses parts of Arizona, New Mexico and Utah, 329 rape cases were reported in 2007 among a population of about 180,000. Five years later, there have been only 17 arrests. Women’s advocates on the reservation say only about 10 percent of sexual assaults are reported.

The young woman who was raped in Emmonak, now 22, asked that her name not be used because she fears retaliation from her attacker, whom she still sees in the village. She said she knew of five other women he had raped, although she is the only one who reported the crime.

Nationwide, an arrest is made in just 13 percent of the sexual assaults reported by American Indian women, according to the Justice Department, compared with 35 percent for black women and 32 percent for whites.

In South Dakota, Indians make up 10 percent of the population, but account for 40 percent of the victims of sexual assault. Alaska Natives are 15 percent of that state’s population, but constitute 61 percent of its victims of sexual assault.

The Justice Department did not prosecute 65 percent of the rape cases on Indian reservations in 2011. And although the department said it had mandated extra training for prosecutors and directed each field office to develop its own plan to help reduce violence against women, some advocates for Native American women said they no longer pressed victims to report rapes.

“I feel bad saying that,” said Sarah Deer, a law professor at William Mitchell College of Law in Minnesota and an authority on violent crime on reservations. “But it compounds the trauma if you are willing to stand up and testify and they can’t help you.”

Despite the low rates of arrests and prosecutions, convicted sexual offenders are abundant on tribal lands. The Rosebud Sioux Reservation in South Dakota, with about 25,000 people, is home to 99 Class 3 sex offenders, those deemed most likely to commit sex crimes after their release from prison. The Tohono O’odham tribe’s reservation in Arizona, where about 15,000 people live, has 184, according to the Justice Department.

By comparison, Boston, with a population of 618,000, has 252 Class 3 offenders. Minneapolis, with a population of 383,000, has 101, according to the local police.

The agencies responsible for aiding the victims of sexual assault among American Indians are often ill prepared.

The Indian Health Service, for instance, provides exams for rape victims at only 27 of the 45 hospitals it finances and, according to a federal report in 2011, did not keep adequate track of the number of sexual assault victims its facilities treat and lacked an overall policy for treating rape victims. Additionally, the health service has just 73 trained sexual assault examiners.

The Justice Department, which has increased the number of FBI agents and United States attorneys on Indian reservations and is seeking to help the Indian Health Service train more nurses, said combating sexual violence was a priority.

“There’s no quick fix. There’s no one thing that will fix the system,” said Virginia Davis, deputy director for policy development in the department’s Office on Violence Against Women. “We’re taking a systematic approach to this — thinking about different ways to solve the problem.”

In the meantime, the problem persists. Lisa Marie Iyotte, 43, who was raped on the Rosebud Sioux Reservation, said prosecutors had never told her why they did not charge the man arrested in that crime. He was later convicted of another rape, and when he was released from prison in 2008 and moved back to the reservation, no one told her, she said. She has not seen him yet.

“When I think about it, I say, ‘What am I going to do?”’ she said. “I don’t know.”

Nine hundred miles away, in the Navajo Nation, Caroline Antone, 50, an advocate for the reservation’s victims of sexual violence who has herself been raped, said sexual assault was virtually routine in her community.

“I know only a couple of people who have not been raped,” she said. “Out of hundreds.”

© 2012 The New York Times Company