BOSTON - After a string of court setbacks unique to Indian country, New England tribes have finally won a big one.

An April 13 decision in the 1st U.S. Circuit Court of Appeals reversed a trend that was tying the hands of tribal governments in resisting state encroachments. The ruling in the case Aroostook Band of Micmacs v. Patricia Ryan, executive director, Maine Human Rights Commission; [et al.]preserves the right of the northern Maine tribe to defend its sovereignty before a federal judge instead of a possibly biased state judiciary.

;'I think it's an excellent decision on a number of different levels,'' said attorney Douglas J. Luckerman, a specialist in tribal sovereignty cases who represented the Micmac. ''It changes the entire momentum of the case law in the 1st Circuit, which was going in a direction that was limiting tribal access to federal courts.''

In most of Indian country, this access would be a matter of course; but the 1st Circuit had adopted a unique (some would say perverse) reading of a technicality that had the effect of turning the tribes back to state courts when they were seeking protection from what they considered state infringements. The problem was especially severe since many tribes in New England won recognition under state and federal settlement acts from the early 1980s with more or less ambiguous limits on their sovereignty.

Although the technicality, called the ''well-pleaded complaint rule,'' was a tangential issue in several recent cases, it laid at the center of the Micmac suit.

The band was seeking a lower court injunction against the Maine Human Rights Commission, which was claiming the right to investigate complaints by three former tribal employees under the state's anti-discrimination law. The Micmac said such investigations would ''impermissibly encroach upon the band's inherent tribal sovereignty.''

The federal District Court said it lacked jurisdiction because the Micmac hadn't satisfied ''the well-pleaded complaint rule.'' It said that even though they invoked sovereignty, they hadn't proven that it was exclusively a federal issue.

The three-judge Appeals Court panel decisively rejected that position in a closely argued 23-page opinion. Although it only dealt with the question of jurisdiction, it clearly said that federal courts in Maine and elsewhere in the 1st Circuit were on the wrong course in refusing tribal cases. ''In short,'' wrote Circuit Judge Kermit V. Lipez, ''inherent tribal sovereignty is a federal common law right that preempts contrary state law, and is therefore a proper basis for an Ex parte Young action.''

(Lipez invoked the famous Ex parte Young ruling to set his decision apart from a contrary 1st Circuit case three years earlier pitting the Penobscot and Passamaquoddy tribes of Maine against a consortium led by large paper companies. The U.S. Supreme Court in the Young case gave federal judges jurisdiction to hear suits against state officials over possible violations of federal rights. Lipez said the Micmac were clearly suing state officials, where the Penobscot and Passamaquoddy were seeking protection against private parties.)

Although the argument might seem like hair-splitting, Luckerman was delighted that the judges went into such detail. ''I could not have asked for a stronger opinion,'' he said. ''They could have handled it in three paragraphs.''

The court didn't reach the tribe's major argument: that unlike the three other federally recognized tribes in the state, the Micmac have undiminished sovereignty because its state settlement act was never properly ratified. That issue will now go to federal District Court.

He said the decision might be a good omen for another major case, the Narragansett Indian Tribe appeal in its suit over the Rhode Island State Police raid on its smoke shop in July 2003. A federal judge in Rhode Island said the raid was justified, but a decision from the Court of Appeals is expected imminently.

The Micmac ruling could also weigh on a third sovereignty case also argued by Luckerman. The Supreme Judicial Court in Massachusetts ruled against the Wampanoag Tribe of Gay Head (Aquinnah) in its fight against regulation by a neighboring town. The tribe has not yet decided whether to seek a review from the U.S. Supreme Court, the only avenue of appeal from a state Supreme Court ruling.

Luckerman argued all three cases within the span of one month in 2004. He recalled that he asked for a postponement of the Micmac hearing but was denied and later learned that it was scheduled as the centerpiece of a historic occasion: the first sitting of a Circuit Court panel in Maine in the Court's two-century existence. All three judges on the panel were from Maine.

Luckerman said that although his research showed they would be sympathetic, he grew nervous as he sat through an opening ceremony in which they gave speeches effusively praising their home state. ''I thought we were dead as a doornail,'' he said.