Norman Mailer, the writer, took a chance on Jack Abbott, the prisoner- writer. The gamble failed. Abbott, paroled from prison partly because of support from Mailer, killed a man in New York and is back again in prison.

Now that Abbott is seen not to have been a fit subject for Mailer's generosity, it is easy enough to unseal the vault of second-guesses and cluck-cluck that Mailer was either a dope or a dreamer to think he could help the lowlife Abbott make it as a writer. Mailer was neither of those.

He was no more than another artist willing to risk leaving the safety of his craft on behalf of someone asking for his help. Mailer's instinct in reaching out to share his time and compassion for an outcast prisoner was humane. That Abbott subsequently killed a stranger was a tragedy. But since he might have killed Mailer as well, it isn't as though--as Mailer's critics are saying--the writer was making the Grand Gesture at no personal risk.

Without doubt, Mailer will think twice about throwing a lifeline to another prisoner-writer. But the harmful effect of the ridicule and contempt being heaped on him is that other writers and artists may be persuaded to keep their distance from problems and problem-people.

To denounce Mailer--to argue that he should stick to writing and leave prisoner rehabilitation to penologists --is to make a wrongheaded case for noninvolvement. It is being said that writers should write, actors act, singers sing, and don't let the line be crossed. If moral issues untidily block the path, hop over them. Society pays cleanup crews to clear away the messes.

Maybe it does, but the pay is low and the messes--colossal ones like Jack Abbott--keep coming. Noninvolvement, costumed as neutrality, appears successful only because no losses need be accounted for. Extending the logic behind the denunciations of Mailer, not only should no writer ever befriend a prisoner, but no one should do much of anything for anyone.

Stop to help someone with a flat tire, and you might end up caught in a mugger's trap. Adopt a child, and he may grow up to create havoc in the community. Work to elect a reform- minded politician, and years later he's caught as a bribe-taker. Is it that much worse for the plans of a famous writer to fail than for the anonymous citizen?

It seems that answer is yes, at least when the famous person is involved in a backfire that has the appearance of "liberal sentimentality" run wild. Jane Fonda will never be forgiven for going to Hanoi, now that the North Vietnamese have turned out to be ruthless conquerors. In the fringes of the diehard right, The New York Times is still ridiculed for some positive stories it ran in the days immediately following Castro's takeover of Cuba. These days, to praise the Sandinistas of Nicaragua is to risk being called naive should Managua not become as peaceful in the next two minutes as Palm Springs.

The double standard that allows artists like Mailer and Fonda to be damned for befriending prisoners or seeking to end a war says nothing when other celebrities turn into shills for certifiable failures. When Jimmy Stewart was telling us about the virtues of the Firestone Tire & Rubber Co., the firm was paying $500,000 in fines--the largest assessment ever--for violating federal safety tests. Frank Sinatra croons for the mismanaged Chrysler Corporation.

Much is now being made of John Reed, the American journalist whose idealism, like Mailer's, was bonded to people whose promise didn't pan out. In the film "Reds," we see Reed committing the unforgivable sin: "flirting with communism." The film has revived the hard judgments against him. He should have known, it is said by the hindsight lobby, that Lenin would replace the czar's brutality with his own.

The sadness is that American literature has too few Norman Mailers willing to take a chance on prisoners. Hollywood has too few Jane Fondas willing to see the enemy as human beings, not devils. On the question of journalists willing to be passionate in their beliefs, the current Progressive magazine asks: "Where, oh where, are today's John Reeds? Can anyone imagine a movie like 'Reds' made about Sam Donaldson or any of the other pretty people on the evening news?"