THE KINGFISH -- At New Playwrights' Theater through September 9.

The people who are presenting "The Kingfish" at New Playwrights' Theater are careful to announce that it takes liberties with the life of Huey P. Long Jr. One guesses this anyway, when the one-man show opens with the Louisiana politician discussing his own assassination.

But apparently there are some liberties that you dare not take with Huey P. Long, no matter how long dead he is. It's probably not safe to kid him, even affectionately, unless you make sure that his transgressions are explained as chicanery in the service of the poor.

This Kingfish of Louisiana, as portrayed by John Daniel Reaves, a former Federal Trade Commission lawyer, is handsome, boyish, charming, outrageous, colorful and impatient with technicalities of law if they interfere with the benefits for the common folk, the chief of these being Huey P. Long.

He wears a white suit, red suspenders and white shoes and brandishes a red-banded straw hat. Because he has an endless ability to produce funny metaphors in which people figure as farm animals, his speeches are riveting and his casual commands are pointed. He never stops being fascinating.

When he comes back from the grave to take potshots at current politicians, he leaves them dead. In his day, he says, you "couldn't come out of the whiskey backwoods" and win office "on the grounds that nobody else was fit for the job and you personally loved Jesus." There was political loyalty then, such as you could not imagine with someone like Governor Jerry Brown -- "It's all they can get him to do to speak to his daddy."

But in this new play -- by Larry L. King, whose "The Best Little Whorehouse in Texas" is a Broadway hit, and Ben Z. Grant, a lawyer and Texas legislator -- as in the official biography of someone still alive and powerful, we get no juicy insights into the subject himself. One minute we see him as a traveling salesman and the next as a rising politician, with little indication of the kind of strength exerted to make that step.

Like his dying words, "Who'll take care of the people?" these glimpses show Long in the light he wished to be presented in. It's what is now called an image, although it's a dazzling image, as made when such things were handcrafted by smart politicians and not standard products produced by group effort.

The least plausible scene is a conversation the Kingfish is shown having with President Franklin D. Roosevelt. Although it's enacted, rather than reported by Long, it shows him demolishing a Roosevelt who is apparently hopelessly naive about political manipulation. This outrageious assumption calls into question the wisdom of taking this Huey Long at his own value.

And yet ironic self-revelation is missing from the portrait. If it's inconceivable that such a wily public figure could betray himself in the first-person format, perhaps a conventional play is needed to set off such a rich character. Or he could just come out and do modern political commentary for us -- it being well established, in this play, that the Kingfish makes the others seem mighty small.