Now and then - say once every hundred or so years - somebody ought to say a kind word about Congress.

Well, cock an ear. With merciful timing considering what's been going on, PBS will broadcast at 9 p.m. Monday "The Congress," an affectionate tour of a much-bashed body.Sandwiched between the X-rated John Tower show and the pending exhibit of Speaker Jim Wright's lingerie, this 90-minute film is an understanding examination of an institution as American as the nearest bowling alley. It may raise Congress' approval rating to rough parity with the Ayatollah Khomeini's.

As demonstrated in its recent salary fiasco, Congress from the git-go has had a genius for klutziness. It's the Inspector Clouseau of politics. Hark to Mark Twain: "There is no distinctly American criminal class except Congress." Even recent Wall Street Journal editorials don't match that.

Lately, conservatives have been the legislative branch's toughest critics. When Roosevelt, Truman and Kennedy occupied the White House, a congressional bloc of Midwest Republicans and Southern Dixiecrats gridlocked much of what they wanted to do. In those days, GOP pompon wielders hailed Congress as the last outpost between the body politic and total insanity.

With the right enthroned in the Oval Office and Democrats gaveling Congress, they shifted their opprobrium up Pennsylvania Ave. The conservative Heritage Foundation recently published a book, "The Imperial Congress," depicting Capitol Hill as equal partner to Alar-treated apple pie as menace to the American Way.

If they're right, it's the enemy Pogo long ago discovered - us. The most representative force in government, and maybe in the country, Congress mirrors the good, the bad and the ugly in us all. As the film points out, Americans invariably berate Congress and find their individual congressman surprisingly decent.

It's been like that since its creation 200 years ago. The first Congress couldn't conduct business for lack of a quorum. When the laggards limped in, they promptly passed the Bill of Rights.

All there in the PBS film, warts aplenty along with eloquent agonies over slavery and preservation of the Union. Joe McCarthy and Joseph Welch (don't thank Eisenhower; he left it to Congress to purge its own cancer). Bosses, martyrs, demagogues, statesmen, buffoons, patriots.

Ken Burns, the film's director, found himself joyfully drowning in Congress as he went along. "They've long been the whipping boy of this democracy," he said, "but they're really us." To Burns, the Tower imbroglio was nothing out of the ordinary. "They're doing exactly what they should be doing. We elect them to make a lot of noise."

A two-headed monster thought up by founding fathers who had learned to trust no one, Congress has served us better than we deserve. If it enacts alien and sedition acts in one generation, it comes along with astonishing humanity in another to offset the callousness of a glitz-imploded Reagan raj. At the moment, it's providing President Bush, who neglected to bring his own, with an agenda he devoutly does not crave.

Comically pompous, exasperating, vain, often petty, Congress manages through some divine dispensation of democracy to reach the right conclusion oftener than not. By the end of the 21st century, it may well deserve yet another two-gun salute.