Never mind what we were taught in school, the American Revolution was a haphazard, extemporized and sometimes slipshod affair. There are no rules for inventing a nation.

The National Archives this weekend opens an exhibit that seemingly dips at random into its almost unimaginable riches of original documents to highlight some of the sideshows of what became a great national movement. Actually, the selection is shrewd. It brings to life, as vividly as stained and faded paper can, the people we call patriots.

And traitors, too: Benedict Arnold's letter to George Washington, written on a British ship to which he fled with his commander-in-chief hot on his heels, reveals him to be a proud fox as well as sly one, and not above leaving his wife behind to slow the pursuit. "She is as good and as innocent as an angel and is incapable of doing wrong," he wrote Washington, after leaving her to her fate.

We all know things were tough at Valley Forge, but the sense of the depth and urgency of the army's trial is heightened by reading Washington's offer of "a reward of Ten Dollars to any person who shall by Nine oClock on monday morning produce the best Subsitute for Shoes [to be] made of Raw hides."

Congress couldn't get its act together or even its members; correspondence bemoans the repeated lack of quorums (Rhode Island's delegates never did show up during one crucial period) and the failure of states to contribute their share of expenses.

There is an eyewitness account of the Battle of Lexington, telling how the dispersing Minute Men were shot in the back; $2, $3, $4 bills in Continental currency, then a $35 one, as printing-press inflation ran wild; Washington's meticulous expense accounts for eight long years; the first territorial land survey under the grid system that shaped our political geography.

It's a messy business, making a republic, but a fascinating one.

THE FORMATION OF THE UNION, 1774-89 -- On view indefinitely in the rotunda of the exhibition hall, Eighth and Constitution NW. Open 10 to 5:30 through March, 10 to 9 from April 1 through Labor Day.