Political analysts have already theorized his candidacy may backfire, splitting black votes from his party to ensure a Reagan runaway in 1984. Critics call him a demagogue with shoddy organization. Backers call him the man who would be King's heir apparent—the most visionary, articulate force in the pulpits and precincts of black politics. Tall, handsome, congenial Democratic presidential contender the Rev. Jesse L. Jackson may not top the polls as the long winter march gets into gear, and he may not be admired by every other black leader, but no one at this juncture could dare claim he hasn't got a prayer.

The illegitimate son of a high school student and her next-door neighbor (Jesse was later adopted by her husband and raised in Greenville, S.C.), Jackson, 42, has thus far used his candidacy to spearhead a grass roots voter-registration drive among his "Rainbow Coalition" of blacks, Hispanics, women and other "locked out, oppressed" groups. His tireless drive is a dazzling study in Hellfire & Barnstorm oratory: "from outhouse to White House...from disgrace to Amazing Grace...from slave ship to championship." Whether his impact on his party is divisive or productive, one thing is beyond dispute: Jackson's on-the-stump flair can make Mondale look like Fritz the Catatonic and John Glenn sound like the the Light Stuff.

A recent appearance before 5,000 at a packed church in a predominantly black ward in North Houston reveals Jackson at his masterly best. He opens with a flurry of political jabs, attacking tax shelters for the rich, welfare for the poor, low black and ethnic representation in Congress; citing narrow Reagan victories in 1980 in states with massive numbers of unregistered blacks, Hispanics and women. The pace pumps up gradually. "We can win!" he shouts. "We can win!" A singer belts out a gospel hymn to a choral-organ background. A woman lost in a state of twitching ecstasy is led away by an unnerved Secret Service agent, trained to look for guns, not grace.

Jackson's just cranking up. When he begins a long tale about his grandma, he hits his stride. His voice comes from some gravel pit in the vocal cords. "She has surviiiiiived to 80," he roars, "always overworked, underpaid, couldn't read or write, but she's a genius." "Yeah, yeah," the all-black audience roars back. "Her eyes are kinda dim now," he says, "but when she could see, ohhhhhhh what she saw." The testifying becomes electrifying. "What she lost in eyesight she gained in insight," he bellows. The voice grows louder, richer. "She heard a voice, and she whispered to me, she said in my ear, 'Keep on keepin' ooooon.' " His hands grip the lectern hard. "Ohhhhhh, when she could seeeeeee."

"Grandma's kinda feeble now," he says softly. "She got arthritis in her fingers and can hardly bend them sometimes. And when we didn't have enough grocery money to make ends meet she could take..." He pauses, rocking sideways like a blues belter, storing adrenaline for a kick-ass climax. "She could take the mold from bread and make medicine...when she had hands." "Yes she did. Yes she did," they all moan together. Hankies wave and wipe tears; hands clutch together. Children stare up at him in awe. "She could take," the voice booms in a grimaced roar of fury, "a potato and peel it one day—when she did have hands. And mash it one day—when she did have hands." "Yeah, yeah." "And boil it one day when she did have hands. And grate it one day. When she did have hands." "Yeah, yes she did. Yes she did." "Her hands are kinda feeble now," he roars, "but ohhhhhh, when she did have hands."

He pauses for the momentum to catch up, turn into delirium. "She can't walk now, but ohhh when she could walk, she walked all night hummin' the Lord's song, and she led me down the road and said to me, 'Choose the high road, never the low road'—when she could walk. She said, 'Put your hands in the hands of the Lord, and the Devil can do no harm.' Ohhh, when she could walk."

Now the voice is so powerful it seems not to be coming from within Jackson but from some other, mightier presence that fills the cavernous church. It becomes suddenly clear the folksy anecdote is also a subliminal parable of 350 years of black America—and it hits its mark. "Now I'm grandma's grandson, and my time has come. I will never forsake her. I will take us to a higher ground 'cause I know rejection. I have known abuse, persecution. I have known jails, I have seen the rough side of the mountain. But I heard the Lord, and I said, 'Lord, you been so good to me, I'll do what you say, go where you send me.' " The bodies are huddled together, standing, tears rolling. Their one voice of jubilation cannot drown out Jackson's. "If you want somebody to feed the hungry, Lord, here am I, send me. If you want somebody to clothe the naked, here I am, send me. I feel like going on that journey now. Nothing can stop us. Our time has come. Here am I, Lord, here am I, here am I, send meeeee."

An hour later Jackson is in an airtight, plushly cushioned car, driving back to a hotel, then in an airtight elevator and quickly ushered into a soundless hotel suite high over downtown Houston. The decompression is alarming. He is weary, solemn but accessible, whispering orders to aides, muttering on the phone, changing his clothes as he works amid near silence. He talks about the "moral imperative" of his run, the "weighty deliberations" with wife Jacqueline and their five children (ages ranging from 8 to 21) about the "dangers of inviting the wrath" of an assassin. "My family is behind me," he says, "but it is a big step. I have faced the occupational hazard of violence all through my public career but it does not preoccupy me."

What helps him through is the "enchanting, romantic" bond with his audiences. "They give me the inspiration. It is hard to feel fatigue out there, but at night I do sleep sound."

The campaign takes a toll at home. "I phone twice a day. I miss 'em. I go from 5,000 people out there tonight to nobody in here now. I may not be alone, but I am lonesome." Prayer and regular fasts help to sustain "clarity and focus" on the run. "My personal discipline is very strong."

So, it seems, is his vision of the mission for which he feels he has been chosen. "Charisma is a gift of the spirit. Those people tonight weren't responding to some meteorite. They're responding to something of substance. There are charismatic people on the stage, too, but their charisma is used to entertain. Mine is to emancipate."