"It brings it all back like a very bad nightmare," Biden said.
It was just days after the weddings that the assaults started, recalled Diane Millich, a Native American and advocate who introduced Biden. She said her ex-husband would mock her defenselessness by calling tribal police and sheriffs, who refused to act until he showed up with a gun.
"All the times I called the police and nothing was done only made my ex-husband believe he was above the law and untouchable," she said.
Linda Fairstein, the former chief sex crimes prosecutor for New York County, said domestic violence remains a huge problem in many Native American and ethnic communities, where women have been less able to seek recourse.
"This gives access to tens of thousands of victims who have just been denied access to the criminal justice system," Fairstein said in an interview.
Although the Violence Against Women Act has been credited with helping reduce domestic violence incidents by two-thirds since its inception, advocates were careful not to suggest that the problem has become any less urgent. Some questioned the accuracy of the new Justice Department data and whether the decline really represented fewer women reporting attacks.
"Having worked in the field, I don't think things are that much better for women," Fairstein said. "That's why these protections are so important."
Associated Press writer Darlene Superville contributed to this report.