By Roy Blount Jr.

Villard. 286 pp. $18.95

AT AROUND the mid-point of this novel, Roy Blount's chaotic narrator interrupts himself (not for the first time in the action), to propose that the great American question -- the great American expression, in other words -- is "Why not?" I have long been of this persuasion. "Why not?" is democratic. "Why not?" is open-minded. It isn't the "Why not?" of a thwarted child or spoiled teenager. It is the response of the toll-taker on a San Francisco bridge when asked by a driver (I read this once in a Herb Caen column) how about a free trip since it was the driver's birthday. It is the voice of the astonished fact-finding right-wing Congressman, who reported excitedly that a Soviet guard said just that to him when asked to allow a minor change in the rules in the birthing days of glasnost. Used in a somewhat over-wrought manner, it furnished Robert Kennedy with one of his better perorations: about how some see things as they are and ask why, and others see things as they might be and ask -- "Why not?"

On Blount's own account, he has now made a stab at every other form of writing except the epic poem. At some lunch, somewhere, a publisher or agent said to him, "Roy, you should try a humorous novel." And the answer was primed and ready to his lips. It was primed and ready, too, when at some subsequent, more businesslike meeting he was told that they saw it as a Washington novel.

So, O.K., there's this guy (call him Guy) and this girl (call her Clementine, why not?) and they meet as '60s college kids when he's kind of a spaced-out writer and she's running nude from the cops, and she becomes Vice President of the United States and then the President is slain, killed, done in by a falling fish near the Great Wall of China . . . Look, if you can face writing a column that is actually entitled "Humor," and in the Atlantic Monthly at that, you are used to taking chances. There is no evidence in the novel that Blount has ever even been to Washington on a day trip (unless perhaps to protest) but that's all to the good. The story of the wife and times of Guy Fox does not depend on anything so literal.

In fact, the few obeisances made to reality are a mistake, and probably the result of another of those pesky conferences. Clementine Fox becomes president at about the time that Gorbachev has taken up exile in New York. Dukakis has been kidnapped in Colombia, Marilyn Quayle is a hostage in Libya and Noriega is back enthroned in Panama City. Suspend disbelief, said the ancients. Disbelief? Forget it, says Blount. He might have done better to leave the whole area alone, since references of this kind are as flat as a gag that depends for its effect on mere name-recognition.

Dialogue, internal and external, is Blount's forte. It doesn't have to have anything to do with the woes of a First Husband (another pun, for which I blame the author). For example, on fatherhood: "Not until you have a son who is a certain age do you realize why it is that old men start wars and send young men off to fight them." Another cliche gone. Or this, on fatherhood combined with the writerly life: " 'If Jackson and I got married we might have a midget child, that's what Mom said,' Lucy told me one day when I was going crazy trying to fix my typewriter so I could write something I didn't really want to write so we could have electricity and mortgage and heat." Blount also has a first-rate ear for overheard speech, especially the speech of morons. Dotards discuss scripture near Lafayette Park:

" 'Times was different back then. It don't have to be literally a snake.'

" 'It didn't have to be back then either.'

" 'No, but I'm sayin' -- '

" 'It might have. Then again it might haven't.' "

There's another of these, too long to quote and in a way too invigoratingly foul as well, between a couple of racist dolts a few chapters further along. Blount also has a gift for Southern speech, in its nicer inflections, and often renders it so perfectly that you don't get it right off. If you can decode Dancy, Clementine's sister, when she says: "Speshly todes the eeyund," why then, you don't need my help.

Just because he doesn't give a hoot for Washington doesn't mean he doesn't care about politics. Indeed, and fittingly, quite the reverse. Much "political" babble is dispelled by this question, which Guy asks the Prez at a key moment: "So we're not balancing the ticket, are we? We're not trying to appeal to people we don't find appealing ourselves?" Yes indeedy.

Too long and too loose, as two great French cities were once called, and over-inclined to the what-the-heck transition, this effort still makes you laugh and briefly invents some neat characters (I almost forgot E.B., one of the funniest bitter blacks since Updike's Skeeter) while asking the age-old question: Pourquoi pas?

Christopher Hitchens is Washington editor of Harper's and a columnist for The Nation.