Sideline Cut: On the week that George Bush delivered his inauguration speech on the theme of freedom, American television was dominated by Ken Burns' long and emotive documentary on the extraordinary life of former heavyweight champion Jack Johnson.

As explained on these pages by George Kimball last October, the filmmaker's research into Johnson's barnstorming assault through the nakedly racist state of mind which governed America in the first half of the 20th century convinced him that the boxer should be given a presidential pardon. A non-binding resolution has since passed both Senate and Congress granting approval for the motion to expunge Johnson of his criminal record for breaching the spurious Mann Act, which made it a crime to take women across state lines "for the purpose of prostitution or debauchery, or for any other immoral purposes" . Johnson served over a year in prison for flouting that convention having fled to Europe through Canada when sentence was passed.

With a dramatised account of Johnson's insolent and daring assault on white sensibilities to come and Geoffrey Ward's comprehensive book, The Rise and Fall of Jack Johnson published as a companion piece to Burns' film last autumn, it has taken a full century for proper reflection on the boxer's career. Although featured in a fictional story by Ernest Hemingway and played by James Earl Jones in the 1968 play The Great White Hope, the black champion was in danger of being categorised as a colourful oddity.

The occasional sporting reference to him was often accompanied by the famous, flickering black and white film clip showing a smiling, dandified black man about to embark on a motoring trip with a glamorous party of starlets and revellers, looking like the original Jay-Z.

Johnson was 30 years of age by the time he famously hunted down Jimmy Burns as far as Sydney, Australia, in 1908 before relieving him of his heavyweight crowd. In front of a hostile, white crowd, Johnson goaded the smaller man with the refrain, "you punch like a woman, Tommy" and provoking the writer Jack London, in one of several diatribes, that some white defender had to be found to "remove the smile from Johnson's face".

Rising to prominence a half a century ahead of Muhammad Ali, Johnson's personality - a skeletal outline of his being suggests someone bold, free, imaginative, vain, selfish, macho, destructive, smart and funny - was like a prototype for the many boxing heroes who illuminated the ring through the rest of the 1900s. In Ward's book, there is a passage where he declines to leave his bed to view Halley's Comet, on the justifiable grounds that while other balls of light would shoot through the sky in future, "there ain't gonna be but one Jack Johnson".

It sounds like vintage Ali. After being convicted under the Mann Act, Johnson apparently sighed and reflected, "Well, they crucified Christ, why not me?" Although Muhammad Ali was extremely serious about religion, Johnson's cavalier comparison of his own circumstances with those of Christ's had serious undertones.

When you consider the manner in which he lived his life during the period of the Jim Crow laws, when the Civil War was still a living memory and the lynching of black people a regular occurrence, it is a wonder that Johnson wasn't simply taken and strung up. Perhaps his fame saved him.

His 1910 marauding of the ageing Jim Jeffries, shamefully forced out of retirement by white public opinion desperate to put manners on Johnson, led to race riots that resulted in over 20 deaths.

Johnson was not an overtly political figure. And it has been argued his hard drinking and brazen consorting with white women, reputable or otherwise, was as much a source of discomfort to the downtrodden black community of the South as it was to the outraged, moral custodians of white society. His great response was to carry on in blithe disregard, declaring Il Trovatore his favourite opera and Alexander Dumas his favourite writer.

In 1929, the urbane New Yorker humorist James Thurber interviewed him for that magazine and although Johnson's diction has been softened in Burns' documentary, Thurber's subject spoke in the broad, accented Southern timbre of Old Jim in The Adventures of Huckleberry Finn. Whatever Johnson's motives in flaunting the material jewels and fineries of white society might have been, he was not trying to imitate the white gentleman, but rather to parody him.

It will be interesting to see, in a week when Bush rhetorically asked if "our generation advanced the cause of our fathers" if the first and wildest man of the boxing game will receive his posthumous pardon. Like old Dubya, Johnson is a son of Texas - albeit from the cotton field as opposed to the oil tradition. Like Johnson, Bush knows what it is like to be the subject of virulent opinion and hostile newspaper articles. And Dubya knows what it is to battle against the bottle, a weakness that gripped Johnson more and more after his boxing pre-eminence waned following his exhausting, 26-round duel against Jess Willard in the burning sun of Arizona.

Boxing experts still peer at what grainy footage remains of his legendary bouts to try to place him in the pantheon of greatness.

Nat Fleischer, the founding editor of The Ring, who saw all the heavyweight bouts from Jeffries through to Joe Frazier, proclaimed Johnson as the best. Elsewhere, he has been deemed a notoriously defensive fighter, damaging with short, counter hooks and preferring to wait until his opponent had reached the point of exhaustion before truly opening up. Of his 105 fights, he had 40 knockouts in 68 wins and 10 losses. He was still looking for fights long after his prime, audaciously challenging Jack Dempsey at the age of 42. But unlike George Foreman, there was no rebirth and he settled into using his prodigious strength in exhibition matches.

But it is not the quality of Johnson's fighting that has drawn a dramatic, serious filmmaker like Ken Burns into casting a compelling light upon him almost 100 years later. It was his sheer daring, his borderline lunatic sense of self-worth and confidence and his proclivity for showing off through a period when the black community was still on its knees.

Whether he did what he did with the advancement of his people in mind is academic.

It was said he was not particularly happy at the idea of Joe Louis emulating his feat in becoming the second black man to claim the heavyweight title some 40 years on.

He was probably too singular and frightening to inspire as Ali later would and too much of an escapist to become a tragic figure like Sonny Liston and too smart to end up like Mike Tyson. But you can trace the lineage right back to him.

And it is probably no coincidence that the resurrection of Johnson comes at a time when the great tradition of heavyweight boxing has all but disappeared off the public radar and is unlikely to return.

Johnson survived a number of car wrecks before finally smashing his Lincoln Zephyr into a tree in 1946s. He was 68. The story is that he left a café in Raleigh, North Carolina, in a rage when told he would have to sit at the back with other "negro" customers. He took off at speed.

Pardoning Jack Johnson is hardly one of the major issues facing George Bush as he begins his second term but it will be fun to see if it comes to fruition. It is a safe bet that the man himself would be tickled pink by the notion. He might have risen from his chambers to witness it.