GIVE MAINE BACK to the Indians? It may sound preposterous, but the Passamaguoddy and Penobscot tribes are now laying legal siege to a large portion of the state - and they are backed, however reluctantly, by the federal government. The 3,000 or so Indians are far from proving their astounding claims, which could involve billions of dollars and 12.5 million acres in which about 350,000 non-Indians now live. Even so, the litigation has disrupted Maine's economy and has spurred the remnants of other tribes to press claims in Massachusetts, New York and elsewhere.

Why has the issue of Indians' rights, with all its emotional freight and legal and historical complexities, suddenly come back East? Because a federal court in Boston ruled that everyone - the national government, the states, the tribes themselves - had been wrong in assuming, for over 180 years, that eastern-seaboard Indians could be dealt with by the states. The ruling upset the treaties which the Passamaquoddy and Penobscot tribes had signed with Massachusetts and Maine between 1794 and 1833. The court also required the federal government to act as the tribes' trustee and perhaps their advocate.

So ancient agreements have suddenly been reopened, casting doubt on all the property rights and investments built up in good faith over nearly two centuries. It is hard to see where the justice lies in this. Even at this distant remove, the Indians may be entitled to a day in court, and to damages if they can prove that their ancestors were cheated or conned. But if our hearts bleed for anyone, they bleed more for the states and citizens who face enormous losses now. They did not set the doctrine of state jurisdiction which has been overturned; they should not be forced to suffer years of economic loss while incredibly tangled lawsuits go on. Because the error, if any, was national, the national government now has to come to the rescue of everyone.

Unless the current negotiations can bring an accord by June 1, the government will have to start the excruciating process of suing Maine and its large landowners, mostly paper companies. Congress has no time to waste. The Maine delegation has proposed legislation which would extinguish the tribes' claims to land and allow them to seek damages in the court of Claims. Congress should take this up seriously and quickly. It seems to be a reasonable approach to cases in which no perfect justice can be found.