WASHINGTON — At 26, Diane Millich fell in love with and married a white man, moving with him in 1998 to a home on her native Southern Ute reservation in southern Colorado where, in short order, her life was consumed by domestic violence.

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.