FARGO, N.D. (AP) – A North Dakota man whose case has been cited by the federal government as the legal standard for prosecuting domestic violence cases on American Indian reservations was sentenced Monday to more than five years in prison.

Roman Cavanaugh Jr., of Fort Totten, pleaded guilty in July to domestic assault by a habitual offender, a charge that allows prosecutors to use previous convictions in tribal courts to bring a case to federal court. The habitual offender statute has been upheld by two federal appeals courts.

Cavanaugh was convicted of domestic abuse offenses in March 2005, April 2005 and January 2008, all in tribal court. The federal charge involves a July 2008 incident in which Cavanaugh was accused of slamming his common-law wife's head against the dashboard of his car and threatening to kill her.

"Because of this statute, Roman Cavanaugh isn't going to be in a position to abuse his wife and kids for a very long time,'' U.S. Attorney Timothy Purdon, of North Dakota, said.

A judge in 2009 threw out the habitual offender charge because Cavanaugh did not have legal representation in tribal court. The 8th U.S. Circuit Court of Appeals reversed the decision in July 2011, and the 10th U.S. Circuit Court of Appeals made the same call that month on a separate domestic violence case.

Brendan Johnson, U.S. Attorney in South Dakota, said the Cavanaugh ruling sent a message to other federal prosecutors that they could bring domestic violence cases to court before it's too late for the victims.

"In the past, we've had to wait until the domestic violence reaches the aggravated assault stage, which means that someone has been seriously, seriously injured,'' Johnson said.

Cavanaugh's attorney, Alexander Reichert, has not been able to get the U.S. Supreme Court to address whether prosecutors should be allowed to use previous convictions in tribal courts. He said Monday that he believes high court justices are waiting for more arguments at the appeals court level before taking on the issue.

"I think the (appeals) ruling is unfair to Native Americans,'' Reichert said, noting that Cavanaugh didn't have a lawyer in tribal court.

The tribal court system on the Standing Rock reservation, which straddles the North and South Dakota border, is one of the few that provides public defenders. Cavanaugh's tribal prosecutions took place on the Spirit Lake reservation in northeastern North Dakota.

"Our goal is to have functioning tribal court systems like they have in Standing Rock, where people have public defenders,'' Purdon said. ``In the meantime, until we get to the point where all the tribal courts are functioning at that level, we're going to use every tool in our toolbox to protect Native women.''

Federal prosecutors in North Dakota have indicted seven cases under the habitual offender statute since the Cavanaugh ruling. South Dakota has indicted 10 cases, including the conviction of former Standing Rock council member Kerby St. John in June.

U.S. District Judge Ralph Erickson on Monday sentenced Cavanaugh to five years and six months in prison, to be added on to another sentence that Cavanaugh is serving for punching his 11- and 12-year-old sons.

Erickson said in court Monday that the habitual offender statute is meant to address an epidemic of domestic violence in Native American communities and called Cavanaugh's charge ``a very serious offense from that standpoint.''

Justice Department figures show that an American Indian woman born in the United States has a 1-in-3 chance of being sexually assaulted in her lifetime, compared with a 1-in-5 chance for all women born in the country.

Cavanaugh told the judge he takes responsibility for his actions and plans to take parenting classes and go through substance abuse treatment in prison.

"I'm beyond sorry for all the things I've done wrong,'' Cavanaugh said.

Erickson, who cited Cavanaugh's eight previous convictions in state and tribal courts for assault and 17 arrests for public intoxication, said he was not impressed with a plea agreement that called for less than five years in prison.

"I can't impose that type of sentence with a straight face,'' the judge said.