THERE IS high drama in the story of Gary Dotson. Briefly released from prison in Illinois last week after having served six years for a rape the victim now says he did not commit, he has just been returned to the penitentiary by a judge who does not believe the victim's new story. The conviction of an innocent man would not ordinarily be big news. Unfortunately, it happens from time to time, even in the best of court systems. Witnesses make mistakes, crucial evidence is uncovered only after the trial, inept counsel fail to make the best case to the jury. But Mr. Dotson's conviction -- if it was in error -- was not due to mistakes but to malice.

Cathleen Crowell Webb testifies now that when she was 16 years old, she made up a story that she had been raped. She did so because she feared she was pregnant by a boyfriend. She identified Mr. Dotson as her attacker after being shown his picture in a police mug book. The choice, she says, was completely at random, since the two had never set eyes on each other. Mr. Dotson was convicted and, at age 22, sentenced to 25 to 50 years for the crime. In the course of the next six years, Mrs. Webb, now married and the mother of two children, claims she was troubled by what she had done, and last month she admitted publicly that she had made up the whole story. But after a hearing last Thursday, Judge Richard Samuels, who presided at the 1979 trial, rejected this confession and recommitted Mr. Dotson to serve the remainder of his term. He can now file a habeas corpus petition asking another judge to release him, or he can petition Gov. James Thompson for clemency or a pardon.

This case is a reminder that protections afforded defendants by the Constitution are there for a purpose. It should be hard to convict an accused, because even mistakes made in good faith are horrifying, and in capital cases irreparable. If Mr. Dotson is ultimately exonerated, he will have lost six years of his youth and freedom. But hundreds were executed for this crime before the penalty was declared unconstitutional in 1977, and no recanting witness or new evidence can alter their fate.