For his 1965 Lewiston, Maine rematch against Sonny Liston, Muhammad Ali invited faded movie character actor Stepin Fetchit to act as a "secret strategist." This astounding turn of events -- in which a recent convert to the Nation of Islam chose to depend on a man whose image as an on-screen shuffler conjures deplored Uncle Tomism -- is the subject of Will Power's new play Fetch Clay, Make Man at Princeton's McCarter Theatre, an impressive elaboration-on-the-facts exercise that could still do with some careful dramaturgical refinement.

As Power reflects it, Ali (lookalike Evan Parke) -- no longer Cassius Clay to himself, to wife Sonji (Sonequa Martin), and to the world -- has a specific explanation for asking Fetchit (Ben Vereen) to his heavily-guarded camp. He knows Fetchit was acquainted with the great Jack Johnson and may have learned from the former champion the secret of what he termed his devastating "anchor punch." Ali figures that adding the swing to his already "I'm the greatest" repertoire will guarantee him winning the fight.

Fetchit's presence, however, stirs controversy among those surrounding Ali, most notably Brother Rashid (John Earl Jelks), the staunch Nation of Islam representative whose job it is to see to Ali's bidding even as he keeps Ali in check. Fetchit also has a transformative effect on Sonji, who's acceded only so far to subjugating herself to Islam dictates but who, at Fetchit's prompting, balks at things like the concealing white garb she's expected to wear and starts showing up in color-coordinated outfits that feature mini-skirts.

While the point Power is ultimately making in this work involves the conflicted elements hampering the progress African-Americans want to make in a white-dominated society, it might help if he could find a faster way to indicate where he's headed. One helpful move might be to eliminate the couple of digressive flashbacks to the early 1930s studio office where mogul William Fox (the always reliable Richard Masur) is signing Fetchit (then Lincoln Perry) to a lucrative contract -- sequences intended to demonstrate yet another manner in which blacks accommodated to whites.

Immeasurably benefiting the play as it stands is the production that director Des McAnuff has put together, working on a smaller scale than is his wont. Using boxing as a metaphor, he's had Riccardo Hernandez design a boxing-ring set in black, white, and shades of gray that simultaneously underscores the themes of internecine battling between and among African-Americans for authority and the complexities of ethical behavior. Costume designer Paul Tazewell responds by dressing the cast on the same black-to-white spectrum -- with the exception of those hot outfits in which the self-liberated Sonji sashays.

McAnuff's cast is also in fighting trim. Parke's delivery of rhymed couplets is deeply joyful. Vereen, who bears a resemblance to Fetchit that has probably never before been noted, plays a man simultaneously broken and ennobled. Jelks' Brother Rashid is unremittingly tough and suspicious, while Martin gives Sonji dollops of sex and backbone and a walk to stop traffic.