Politics is not a profession for people who crave solitude. However, John McCain, a Republican congressman seeking a Senate seat, has had enough solitude to last a lifetime. It was solitude handed out by Hanoi, which means it was interspersed with torture.

He was born in the Panama Canal Zone and into the Navy. His father, Adm. John S. McCain, commanded U.S. forces in the Pacific during Vietnam. His grandfather, another admiral, was commander of aircraft carriers in the Pacific under Adm. Halsey during World War II. So it was all in the famiy for the grandson to be flying an A-4 Skyhawk off a carrier and over Hanoi on Oct. 27, 1967. And it was natural for his captors to call him "the crown prince."

The prince was the worse for wear. When is plane was hit, he ejected during a nosedive and broke bones in both arms and one leg. He fell into a lake in central Hanoi. A mob bayoneted him and smashed his shoulder. He was a prisoner for 51/2 years. Because he was properly obstinate, he was in solitary confinement for most of that time.

His hair quickly turned white, and his weight fell below 100 pounds. Every day for two years, one of his guards ordered him to bow and then knocked him down. It was what is known as a consciousness-raising experience, one that he says made him acutely sensitive to the humiliations of discrimination.

On this day the conservative congressman is getting more sensitivity training from black leaders at a church lunch. Working the tables, he practices the tactile side of politics, shaking hands, slapping backs, gripping forearms, kneading shoulders.

To say Arizona is booming is to settle for too limp a verb. But booms do not lift everyone skyward, and the black leaders give McCain a grilling. Every Arizona politician knows the many forms poverty can take: 27 percent of the state is Indian reservations, one of which spills into Utah and New Mexico and is larger -- and much poorer -- than West Virginia.

McCain is a natural politician. He was elected "president" of Congress' freshman class of 1982 and was reelected to the House in 1984 with 78 percent of the vote. In 1982 he had lived in Arizona less than two years. To the charge that he is a carpetbagger, he replied that he had never lived long anywhere except Hanoi.

Most recent heavy-hitters in Arizona politics (Rep. Mo Udall, former representative John Rhodes, Gov. Bruce Babbitt, Sens. Dennis DeConcini and Barry Goldwater, who is retiring from the seat McCain is seeking) are from families whose records of public service run deep into the state's prehistory, known here as "pre-air conditioning." This feudal tendency is a charming oddity in the state that is the newcomer among the Lower 48 -- the last to join the Union. But, then, only in an odd state would the legislature proclaim bolo ties the official state neckwear.

Most Arizonans were born elsewhere; indeed, it sometimes seems that most are still unpacking. More than one-third of the registered voters -- 450,000 of them -- have arrived since 1981. Very few of today's Arizonans were voting when Goldwater became a senator 33 years ago. Arizona has had only eight senators, thanks in part to Carl Hayden, who served from 1927 to 1969, retiring when he was 92.

McCain almost certainly will become the ninth. A recent poll has him leading his opponent, Richard Kimball, even among Democrats, and by 25 points statewide. In Maricopa County (Phoenix), where more than half the voters live, McCain's lead is almost 40 points.

Kimball began by running a populist campaign against the Phoenix "establishment," as personified by a prominent publisher who is a friend of McCain. Kimball said the publisher exemplified the attempt to impose a Senate choice. In December this publisher resigned in disgrace when it was learned that for years he had misrepresented his military record; he had never been in the military, but claimed an illustrious record as a fighter pilot.

However, Kimball must eventually run against McCain himself, and Kimball seems accident- prone. He has said (to Phoenix Gazette columnist John Kolbe) such vertigo-inducing things as: he is running "because my experience mirrors where the state ought to be going." And: "We can be physically (sic) responsible without abandoning social issues." Say what? If McCain manages to make this race close, he has a knack for finding danger in blue skies.