When Tony Blair evoked Colin Powell's rise from poverty to secretary of state and questioned whether it could happen here, he highlighted one of America's great racial successes and exposed one of Britain's most gaping flaws. He also opened the Pandora's box of race, class and ethnicity on both sides of the Atlantic.
For it is no coincidence that Powell rose through the army. The right to fight for America has, at times, been the focal point for many crucial debates about race and citizenship. It was an issue that raged fiercely during both the American revolution and the civil war, when even northern troops fighting slavery were reluctant to arm African-Americans. But it was not until after the second world war that blacks and whites started to fight in formally integrated units. African-Americans were allowed to carry guns with their fellow white citizens before they were permitted to eat hamburgers alongside them.
Today, around 27% of all US personnel on active duty are black - more than twice the proportion in the country as a whole. "One major institution contradicts the prevailing race paradigm," write Charles Moskos and John Butler in their book, All That We Can Be. "It is the only place in American life where whites are routinely bossed around by blacks. The institution is the US Army."
It is in this environment that Powell could thrive. That could not happen here. The British army has a history of racism that would make the Metropolitan police blush. In 1994 Mark Campbell left the Life Guards after his bed was soaked in urine and he was left a note saying: "There is no black in the Union Jack." In 1990 Richard Stokes left the Household Cavalry after receiving hate mail and having a fellow soldier throw a banana at him. The army is now doing its best to both improve its image and address the racism within its ranks. But it remains an unattractive prospect for Britain's ethnic minorities. Despite the high levels of unemployment particularly among Bangladeshis, Pakistanis and Afro-Caribbeans, only around 1% of the British armed forces come from ethnic minorities - less than a fifth of the proportion in the country at large.
But Powell's personal success should not be confused with the advancement of black Americans as a whole. For while he could not have got where he is without being talented, other factors undoubtedly helped. Born to Jamaican parents, he was not schooled in the inferiority of the segregated south. The experience of those of Caribbean-origin in America, from Harry Belafonte to the country's first black congresswoman, Shirley Chisholm, has offered considerably more hope than for either African-Americans there or Afro-caribbeans here.
And then beyond national heritage there is class - a factor that has always allowed the limited progress of a minority within the minority. Powell's colleague, national security adviser Condoleeza Rice, was born in Birmingham, Alabama, which Martin Luther King branded as "probably the most thoroughly segregated city in the United States". Rice's story - she is the daughter of a preacher - illustrates that even within the confines of southern racism a class system among blacks flourished and is now bearing fruit at the highest levels. When people express their admiration, Rice responds: "My family is third-generation college-educated - I should've gotten to where I am."
In Britain we have black individuals with wealth, influence and status, but nowhere near the critical mass needed to call it a black middle class. But take a five-minute drive from the White House to the impoverished black areas of Washington DC, where child mortality is at third-world rates, unemployment is high, crime pervasive and poverty endemic, and you see that for everyone that makes it to the top in America, many are left at the bottom.
The fact that we cannot boast a black cabinet minister is lamentable. The fact that we do not have the destitution or despair of the black American underclass is laudable. Colin Powell could not happen here; nor could one third of young black men be in jail, on probation or on parole. A vital distinction, for a party that seeks to advance the interests of the many, and not just the few.