John Brown is one of America's historical enigmas -- in legend a martyr but to most of his contemporaries a crazed zealot. The present-day excesses of some militants in behalf of various causes lend new interest to a dramatization of Brown's story, which the Source Theatre has tried to tell in "The Holy Terrorist," now playing at the Warehouse.

Howard Roman's script focuses on two central events in Brown's career as an abolitionist -- one in which he and three sons murder a man and his son because they are proslavery (historically, five were killed) and the famous raid at Harpers Ferry, in which Brown and a band of 18 men tried to seize a U.S. arsenal. He was hanged as a traitor a few months later, but for generations of schoolchildren his body "lies a-moldering in the grave, but his Soul goes marching on."

The production owes much to director Robert McNamara, who has infused it with impressive energy and vitality and makes effective use of a large cast moving between numerous locations and events. But neither he nor Roman comes to grips with the central dilemma: the justification of criminal acts in the name of a good cause. The script and the production take the position that Brown was a maverick exercising a bent for murder, rather than a dedicated if overzealous abolitionist.

Accuracy is not necessarily the point of good drama, but the trouble with "The Holy Terrorist" is that the author seems to have wavered between concentrating on the story of one man's tragedy -- the loss of his sons, supporters and eventually his own life -- and the larger historical picture, the debate over his methods and the slavery issue. As a result, neither element is fully realized.

The problem is not helped by Source artistic director Bart Whiteman's portrayal of Brown. Whiteman has chosen to underplay, possibly as a counterpoint to the thunderous activity that often mills around him. His religious conviction is somehow unconvincing, sounding more like an excuse for violence than the expression of a man who many viewed as insanely propelled by "God's word." Despite Whiteman's ample size, his Brown seems unweighted, and despite his skill as an actor, there is little sense of a magnetic character.

There are many excellent performances, and it is through them that the emotional intensity of the play is released. Richard Harrington as the slain proslaver, Michael Franz as one of Brown's northern supporters, Christi Engel as Brown's daughter-in-law, Michael Judge in several roles and Beverly Bowman as the wife of the proslaver are a few of the standouts in a generally strong cast. The musical commentary of throbbing drums is effective as well, adding tension and texture.

Roman has successfully provided a stimulating evening. The shortcomings are frustrating because the aim is so high.