Her story of beatings and threats, reconciliations and divorce — painfully common among Native American women — had a twist. Because her husband was white, the Southern Ute Tribal Police could not touch him, and because she was a Native American on tribal land, La Plata County sheriff’s deputies were powerless as well. She said she tried going to federal law enforcement, which did have jurisdiction, but that went nowhere.

After one of his beatings, she said, he even called the county sheriff himself to prove to her that he could not be stopped. Only after he stormed her office at the federal Bureau of Land Management and opened fire, wounding a co-worker, was he arrested. And even then, law enforcement had to use a tape measure to sort out jurisdiction, gauging the distance between the barrel of the gun and the point of bullet impact to persuade the local police to intervene.

Obscure as it might be, the issue of tribal court powers and Ms. Millich’s jurisdictional black hole has become the last remaining controversy holding up Congress’s broad reauthorization of the landmark Violence Against Women Act. The Senate on Monday is expected to approve the 218-page bill with broad, bipartisan support.

But in the House, Republican negotiators are still struggling over a 10-page section that would, for the first time, allow Native American police and courts to pursue non-Indians who attack women on tribal land. Supporters and opponents of the language acknowledge the plight of women like Ms. Millich. Native American women are two and a half times more likely to be raped. One in three will be assaulted, and three out of five will encounter domestic violence, said Senator Tom Udall, Democrat of New Mexico.

“It was just crazy, now when I think back on how insane it was,” Ms. Millich said in an interview.

If a Native American is raped or assaulted by a non-Indian, she must plead for justice to already overburdened United States attorneys who are often hundreds of miles away.

“Native women should not be abandoned to a jurisdictional loophole,” Mr. Udall said.

But conservative opponents say the Senate’s language goes too far, empowering courts that are not equipped for the job and depriving defendants of constitutional rights without nearly enough recourse to federal courts and no guaranteed protections like those afforded by the Bill of Rights.

“This is a bill which could do so much good in the battle for victims’ rights, but unfortunately it is being held hostage by a single provision that would take away fundamental constitutional rights for certain American citizens,” Senator John Cornyn, Republican of Texas, said on the Senate floor on Thursday. “And for what? For what? In order to satisfy the unconstitutional demands of special interests.”

The fight is pitting a dry legal position against an emotional and politically potent one. Native American groups and women’s rights advocates say they are not special interests. They are voters, however.

“Let’s just talk politics here,” said Representative Tom Cole, Republican of Oklahoma, who has been leading negotiations to end the impasse. “This will have passed the Senate. The president’s for it. And we’re holding up a domestic violence bill that should be routine because you don’t want to help Native women who are the most vulnerable over a philosophical point?”

Mr. Cole and another senior Republican, Representative Darrell Issa of California, have met repeatedly with Representative Eric Cantor of Virginia, the House majority leader, to try to get Republicans past the tribal courts issue. They have proposed extending Native American court powers but also offering non-Indian defendants a chance to appeal to federal law enforcement after arrest and after a conviction. Representatives from the National Congress of American Indians met with Cantor staff members last week as well — and they have backed the Issa-Cole compromise.