The Definitive Treaty of Paris, signed on September 3, 1783, wasn't definitive and didn't settle anything that hadn't already been decided by the force of American arms and the lack of British will.

But, still, however and nevertheless, we have decided to make a great hooraw over the bicentennial of the act that formally ended the American Revolution.

And why not? Any excuse to haul out dusty diplomatic documents and original letters of the Founding Fathers is a good one, and the National Archives has gotten up a small display that includes the treaty itself. After a majestic throat-clearing preamble it finally bites the bullet:

His Britannic majefty acknowledges the faid United States . . . to be free, fovereign, and independent ftates; that he treats with them as fuch, and for himfelf, his heirs and fucceffors, relinquifhes all claims to the government, property, and territorial rights of the fame, and every part thereof.

"That much had already been decided, on the battlefield at Yorktown, by the sentiment of the British Parliament and people, and in the preliminary treaty signed the year before," said Milt Gustafson, Archives diplomatic historian. "The rest of the treaty dealt with boundaries, fishing rights, claims of loyalists, and so forth. None of those agreements was effective, and each problem had to be settled separately, in some cases many years later.

"But to keep things orderly we must date the end of the revolutionary period sometime, and the signing of the treaty is as good as any. The funny thing is, we're making much more of a fuss over it now than they did at the time, and the centennial of the signing was all but ignored."

The Assembly of Pennsylvania did commission Charles Willson Peale to build a triumphal arch for "Public Demonftrations of Joy" over the definitive treaty, but it burned down before the festivities could commence, so they laid the whole program over to the spring of 1784.

That and other tidbits are to be found in the National Portrait Gallery's Treaty of Paris exhibit, capped by a life-size portrait of George III that depicts him as just the sort of imperious creep we colonial brats thought he was.

Curators James G. Barber and Frederick S. Voss have assembled a fine collection of portraits of the leading actors in the treaty negotiations, including some that are so perceptive that at a glance they tell all one needs to know about the man.

The captions are not only graceful and informative -- a rare thing in this wordy and obscurantist town -- but brief and vigorous.

The portraits are worth studying. The one of John Adams, by John Singleton Copley, describes better than words why a whole lot of people didn't like John Adams, while suggesting why Abigail did. One hopes British commissioner David Hartley got a cut rate on the portrait he had done by George Romney, because Romney got the treaty date wrong. And why is King Charles III of Spain shown arrayed in full-dress armor and decorations but holding a plain stick instead of a scepter? FREE AND INDEPENDENT -- Through January at the National Archives. BLESSED ARE THE PEACEMAKERS -- Through November 27 at the National Portrait Gallery.