Federal prosecutors can’t always use past tribal court convictions as proof of a defendant’s criminal history, a panel of the ninth US circuit court of appeals found in a Montana case.

The determination came Tuesday as the three-judge panel ruled that two federal counts of domestic assault filed in 2011 against Michael Bryant Jr must be dismissed.

The judges said Bryant was convicted of previous crimes in Northern Cheyenne Tribal Court and served time in custody but didn’t have an attorney. The judges said those convictions would not be considered legal under the sixth amendment of the US constitution, which guarantees a defendant the right to an attorney.

Northern Cheyenne tribal court rules say defendants can hire their own attorneys but it does not guarantee an attorney will be appointed.

The US attorney’s office in Montana argued that tribal courts aren’t governed by the US constitution, and that Bryant’s convictions were legal under tribal law. The eighth and 10th circuits have agreed with similar arguments.

“We recognize our holdings place us in conflict with two other circuits,” ninth circuit justices Harry Pregerson, Richard A Paez and Paul J Watford wrote.

While Watford agreed with the decision in Bryant’s case, he argued the case law on which the judges based their decision case should be revisited.

“The implication is that, if the defendant lacks counsel, tribal courts are inherently suspect and unworthy of the federal courts’ respect,” Watford wrote.

Watford also noted that the ninth circuit is inconsistent because another decision allows tribal court convictions to be used as a basis to charge someone with being a felon in possession of a firearm, even if that conviction didn’t meet sixth amendment standards.

“That seems illogical,” Watford wrote. “If anything, we would want to be more cautious about the use of uncounseled prior convictions in prohibiting firearms possession, because that prohibition impinges upon what would otherwise be a fundamental right.”

The US attorney’s office could ask for the entire court to consider the matter or seek to raise the issue with the US supreme court.