To the already long list of improbable White House get-togethers - Elvis Presley and Richard Nixon, Yitzhak Rabin and Yasser Arafat, Princess Diana and John Travolta - we will be able to add the names of a black professor and a white policeman at the centre of a national uproar over race relations.

Cambridge police sergeant Jim Crowley and Henry Louis Gates, the Harvard scholar he arrested after responding to a report of a possible break-in at Mr Gates’s home, will sit down with Mr Obama on Thursday for a conciliatory beer.

Admittedly, it is tempting to view the invitation as the ultimate conflation of the age of Obama and the age of Oprah.

Aside from the choice of beverage, there is something very daytime television, something very soft focus, something very soft sofa, about this attempt to defuse the controversy.

Mr Gates was held for disorderly conduct, after he allegedly criticised police behaviour during the incident at the scholar’s home on 16 July. President Obama - a friend of Mr Gates - got involved in the case, saying the police had acted "stupidily”.

Yet startling and novel as Mr Obama’s attempts to defuse the controversy are, he is merely upholding a long tradition. Presidential racial politics have often been conducted with gestures, symbols and photo opportunities, and this is but the latest example of a well-worn genre.

Ever since the war, when black voters - or the Negro vote, as it was then known - became a potentially election-deciding force, presidents have embraced symbolic gestures, for the simple reason that they allow them to appeal to blacks without alienating whites.

Often the gestures have been rather obvious. Sometimes they have been so subtle as to be almost subliminal.

Alert to the growing strategic importance of the black vote in key northern battleground states, Dwight D Eisenhower invited the black contralto, Marian Anderson, to perform at his 1956 inauguration. It was a gesture especially redolent with meaning, since in 1939 she had been barred from singing at Constitution Hall in Washington.

His successor, John F Kennedy, happily extended a White House invitation to the world heavyweight boxing champion, Floyd Patterson, hoping it would compensate for his stubborn refusal to offer similar hospitality to Martin Luther King.

Not to be outdone by President Eisenhower, JFK also invited Marian Anderson to sing at his inaugural, but then went a few notable steps further by dancing with black women at the balls later on that night.

This kind of imagery has also been used in reverse, using more harmful symbolism.

Ronald Reagan delivered the first major speech of his 1980 campaign in Philadelphia, Mississippi - the town memorialised in the Hollywood movie, Mississippi Burning - where three civil rights workers were brutally murdered in 1964.

The subject of his speech was "states rights”, for some a euphemism for white supremacy.

In 1992, the then Governor of Arkansas, Bill Clinton, famously attacked the black singer Sister Souljah; and, more infamously, made sure he returned home to Little Rock mid-campaign to oversee the lethal injection of Ricky Ray Rector, a brain damaged black man who had killed a police officer.

These kinds of techniques are so commonly deployed, largely because they can have such a dramatic effect.

Even as black leaders attacked him for his timidity on civil rights, Mr Kennedy enjoyed high approval ratings among black voters, partly because they had been such full participants in his inaugural celebrations.

Nothing underscored Bill Clinton’s moderate, New Democrat credentials better than his attack on a black hip-hop artist.
So history suggests it would be foolish to underestimate the reconciliatory potential of this Budweiser moment, however dubious it sounds.

After all, conflict resolution often turns on the mutual and public acknowledgement of each side’s fears and grievances, along with the photo-opportunity that accompanies it.

By extending this invitation, Mr Obama also appears to be signalling that neither Prof Gates nor Sgt Crowley was wholly in the right or wholly in the wrong.

The beer at the White House, then, marks an attempt to balance white fears about black lawlessness, whether real or imagined, with black middle-class grievances about white racism, whether real or imagined.

Throughout the campaign, Mr Obama deliberately de-emphasised his race. To be a history-defying candidate he became a history-denying figure, and left others to attach racial meaning to his candidacy.

Since winning the presidency, however, he has been much more expansive on the issue, starting with his victory speech at Grant Park in Chicago, where he located his achievement in the context of Montgomery, Birmingham and Selma, the climactic moments of the civil rights era.

During his recent speech before the civil rights group, the NAACP, he made reference to these events to emphasise his theme of black self-improvement.

"I know that nine little children did not walk through a schoolhouse door in Little Rock so that we could stand by and let our children drop out of school and turn to gangs for the support they are not getting elsewhere,” he said accusingly.

The Gates controversy has been harder for him to deal with because it deals with more awkward history and touches on the ambiguous legacy of the civil rights era.

White support for the civil rights movement started to wane when blacks demanded affirmative action and reparations. Conversely, racial profiling is an area where blacks feel they are still treated as second-class citizens.

This controversy not only taps into that milieu, but inadvertently brings together two unlikely protagonists: Prof Gates, one of America’s most eloquent advocates of affirmative action, and Sgt Crowley, who for five years taught a class on racial profiling at a local police academy which cautioned against stereotyping.

When you reach back into American history, you often find that racial progress has come when the case for reform or reconciliation has been framed in Biblical language or used faith-based allegories.

Rev King’s I Have a Dream speech is the most obvious and glorious example.

Now Barack Obama is conjuring up a modern-day parable: the story of the professor, the policeman and the president. But can he turn beer into progress?

BBC News