Any world leader who doubts the power of speech need only recall Winston Churchill. He stuttered as a youth and had a lisp, but it is Churchill's eloquence that helped keep England's spirits from plummeting during the war years. James Humes is a Churchill scholar who recently wrote a book about the legend's formative and famous years (Churchill: Speaker of the Century, Stein and Day) and has written speeches for president's including Dwight Eisenhower and Richard Nixon. According to Humes, Jimmy Carter "has not been served well by his speechwriters" at a time when America needs presidential inspiration.

"Eloquence is needed for the unpalatable, not the palatable," says Humes, who suggests Carter speaks best in small groups with a quasi-spiritual text. "I'd suggest he pick a speechwriter who is a minister instead of a Brooklyn intellectual. I don't want him to necessarily give sermons, but there's nothing wrong with the King James language -- Lincoln and Martin Luther King both used it."

As president of Kingstree Communications in Newport, R.I., Humes advises heads of major corporations on speech delivery and, but request, offered these thumbnail critiques of other candidates:

-- Ronald Reagan: Good timing, good delivery, thanks to his early work as a radio announcer and actor.

-- Edward Kennedy: He's improved through practice. Not as good when he extemporizes -- punches too much.

-- George Bush: Best with questions and answers, which helped him win in Pennsylvania. Not a good speechreader, though he's improved more than any candidate during his presidential bid. Gestures seem mechanical.

Humes suggests Carter write his own speeches on subjects as sensitive as Iran and inflation and then let a speechwriter polish the text. It's the only way he might come close to Churchill who, as Edward R. Murrow once noted, "is . . . the only man who ever prophesied history, made history and recorded history."