As pointed out above, Muhammad Ali never served any of his five year sentence for draft evasion, as the verdict was overturned unanimously by the United States Supreme Court.
However, it's not quite true to say he never did any time behind bars. While his case was under appeal, he was imprisoned in Dade County jail for ignoring traffic citations. He was released after ten days on a general Christmas amnesty for all minor offenders.
For those interested in the Ali draft case, here is the account of the Supreme Court’s deliberations, taken from The Brethren by Bob Woodward and Scott Armstrong:
Brennan was the only Justice who really wanted to hear the Cassius Clay case (Clay v. U.S.).
Clay, who had changed his name to Muhammad Ali in 1964, had been sentenced to prison for five years for refusing in 1966 to take the traditional step forward and be inducted into the Army. [Note: Woodward and Armstrong got the date wrong. Ali refused induction on April 28, 1967, and was convicted and sentenced later that same year.] The former world heavyweight-boxing champion based his refusal on religious grounds, claiming that, as a Black Muslim, he was a conscientious objector and thus entitled to exemption from military service.
Apart from the complicated war and draft issues, there were racial overtones to the case. Ali was one of America’s best-known and most popular black athletes. His appeals had taken six years and, stripped of his title by the World Boxing Association, the fighter had been banned from boxing for nearly four years at a loss to him of millions of dollars in purses. Public sympathy was growing for Ali, but at the same time the Black Muslim faith had been portrayed as separatist, antiwhite and bizarre.
The case had already come up to the Court two terms before, and the conference had voted not to hear it, thus letting Ali’s conviction stand. A last-minute revelation by the government that Ali had been overheard on a national-security wiretap had prevented the decision from being announced. The technicality had allowed the Court to send the case back to the lower court for further hearings.
The Justices had hoped it would not come up the ladder again, but when it did, Brennan finally persuaded his colleagues to grant cert.
Given Ali’s prominence, the Justices would allow him the satisfaction of having his case reviewed by the highest court in the land, a satisfaction given few defendants. None of the Justices believed Ali had a chance of winning.
At oral argument, Solicitor General Griswold pointed out that Ali had left little doubt that “if the Vietcong were attacking his people, the Muslims would become involved in that war.” Moreover, Ali had been quoted in the press as saying, “I am a member of the Muslims and we don’t go to war unless they are declared by Allah himself. I don’t have no personal quarrel with those Vietcongs.” Since Ali would participate in a holy war, he was not really a conscientious objector, Griswold said.
On Friday, April 23, with Marshall recused because he had been Solicitor General when the case began, the conference decided, 5 to 3, that it agreed with Griswold. Ali was not really a conscientious objector and should go to jail.
The Chief immediately assigned Harlan to write the majority view. But as Harlan’s clerk began preparing a draft opinion, he was persuaded by another clerk who had read Alex Haley’s Autobiography of Malcolm X to reconsider the question of Ali’s opposition to war. Reading the Message to the Black Man, one of the most trusted texts of the Black Muslims, the clerk became convinced that Ali’s willingness to fight in a holy war was irrelevant. For all practical purposes, Ali was opposed to all wars.
Harlan was not inclined to buy any of this. But he agreed to take home his clerk’s background materials and study them in the specially illuminated library of his Georgetown townhouse. The next morning, he had a surprise for his clerks. He had read the materials and he agreed wholeheartedly, wanting them incorporated, as written, into his draft. Harlan was persuaded that the government had mistakenly painted Ali as a racist, misinterpreting the doctrine of the Black Muslims despite the Justice Department’s own hearing examiner’s finding that Ali was sincerely opposed to all wars.
Harlan wanted to confront the Justice Department’s misrepresentation and state explicitly that there had been “no basis in fact” all along for them to say that Ali was not really opposed to all shooting wars. Because there had been no indication outside Harlan’s chambers that his view had changed, when his memo suggesting reversal of the conviction was circulated, it exploded in the Court. Burger was beside himself. How could Harlan shift sides without notifying him? He was even more irritated by the incorporation of Black Muslim doctrine in the opinion. The draft said the Black Muslim doctrine teaches “that Islam is the religion of peace…and that war-making is the habit of the race of devils [whites]…[and that Islam] forbids its members to carry arms or weapons of any kind.” Harlan had become an apologist for the Black Muslims, Burger told a clerk. Moreover, his switch tied the vote, 4 to 4. That would, however, still mean that Ali would go to jail.
The Chief was not about to shift his own vote. Nor were Black, White or Blackmun, the other members of the original majority. They were particularly disturbed that Harlan wanted to stress the government’s twisting of the facts. Harlan’s view could mean that all Black Muslims would be eligible for the conscientious objector status.
The Court year was coming to a close. If the Court remained deadlocked, Ali would finally go to jail for draft evasion. Since decisions in which the Justices were equally divided were not accompanied by opinions, Ali would never know why he lost. It would be as if the Court had never taken the case.
Stewart was particularly upset by this prospect. He proposed an alternative: the Court could simply set Ali free, citing a technical error by the Justice Department. The proposal had several advantages. For one, the ruling in this case would not become a precedent. It also would not broaden the categories under which others might claim to be conscientious objectors.
Gradually, all but the Chief agreed to go along with Stewart’s plan, giving Ali seven votes. [Douglas’s concurrence retained language making it obvious that it was originally a dissent. His clerk, who normally would have corrected it, refused to work further on the opinion after Douglas insisted on retaining an incorrect statement of the Black Muslim position on holy wars.] That left Burger with a problem. If he dissented, it might be interpreted as a racist vote. He decided to join the others. An 8-to-0 decision would be a good lift for black people, he concluded.
Stewart drafted the final unanimous per curiam. Ali’s victory was announced on June 28. He heard the news in Chicago. “I thank Allah,” Ali said, “and I thank the Supreme Court for recognizing the sincerity of the religious teachings I’ve accepted.” He did not know how close he had come to going to jail.
