One of the unwritten laws of the dance world appears to be that somewhere along the line nearly every ballet choreographer will do a commedia dell'arte number. For Eliot Feld, it was the opus he calls "Theatre," created in 1971 to the Strauss "Burlesque," and mounted by the Feld Ballet (which hasn't done it in about five years) at the Kennedy Center Opera House last night. The piece shows both the up and down sides of Feld's talent in rather strong relief -- his theatrical savvy and imagination on the one hand, and his difficulty in sustaining a continuous developmental thread on the other.

Being the modern sophisticate that he is, Feld isn't about to give us our harlequinade straight, so he frames the whole charade with backstage glances that play on the polarities of mask and "reality." John Sowinski is completely disarming as a lovelorn, melancholy clown, Pierrot, who is teased, mugged and generally victimized by such other characters as the brittle lovers Colombina (Christine Sarry) and Arlecchino (Richard Fein), the beak-nosed grotesque, Pulcinello (Patrick Cea), and assorted brigands and tarts. Along the way there's a splendid bravura solo brilliantly danced by Fein, and a sparkly one for Sarry.

It's all quite diverting, but at the same time, frustratingly thin and elusive -- if you blink, you've missed what little narrative thread there is. The Strauss score provides a large, sonata-form structure, but Feld's choreography has no corresponding scaffolding; it just goes from one bit of "business" to another. Character and atmosphere alone don't stretch well enough over a half-hour.

Feld's natural inclination is toward short takes, which is why so many of his pieces fall into suite form. Even "Circa," which was stirringly repeated last night, sags in the middle because Feld's redundancies can't fill out Hindemith's broad musical arches; the ballet makes it, however, on the sheer beauty and inventiveness of its movement.In "Half Time," which closed the program, Feld is in his element -- a series of Morton Gould marches and parade numbers. Here the choreography gives us brisk snapshots of musclemen and pom-pom girls, illustrating the proposition that while we're all suckers for the old Red, White and Blue, part of being American is also a readiness to smile at even our most hallowed national symbols and rituals.