A discreet subtext of US Secretary of State Hillary Clinton’s seven-nation tour of Africa was the unspoken fact that she is struggling to assert her primacy in conducting American foreign policy — with, so far, mixed results.

The tone of what she had to say had already been set by her boss, President Barack Obama, when he made his inaugural African stop in Ghana in June.

Obama’s speech before Ghana’s parliament, to which the entire continent listened keenly, dictated the theme for Mrs Clinton’s follow-up lectures on governance and democracy to the countries she visited on her 11-day itinerary.

Yet in terms of US foreign policy priorities, Africa remains low on the list. For Mrs Clinton to be relegated, as it were, to this sort-out-the-Africans role when more pressing hotspots are flaring around the world hinted she is not as entirely in command of America’s foreign policy apparatus as her status would suggest.

Regarding the Obama administration’s global priorities, top on the list are cleaning up America’s hitherto tarnished international image, tackling climate change, and improving the superpower’s international trade competitiveness.

On these three issues, there is no question at all that it is the White House that is driving the agenda.

Regarding the image problem, for which George W. Bush was so recklessly responsible, Obama has personally sought to correct that through his international forays, most notably in the speech to the Muslim world he delivered in Cairo on June 4.

On climate change, Obama has taken it upon himself to push a “clean energy” policy not just domestically but also in the lobbying he undertook during the G-8 summit in Italy last month.

And as far as economic relations go with America’s largest sovereign creditor — China — that sensitive job has largely been relegated to Treasury Secretary Timothy Geithner.

Then there is Vice-President Joseph Biden, who previously served as the chairman of the Senate Committee on Foreign Relations, which is a powerful post. Biden has successfully leveraged his foreign policy experience to encroach on Mrs Clinton’s turf, with Obama’s tacit approval.

The White House has in fact been eager to use Biden to mend relations with Europe, which were so badly frayed by Bush’s cowboy diplomacy.

Recently, Biden was dispatched to Eastern Europe to sell US engagement policy there. He also took a detour to Georgia, a renegade former Soviet republic that Russia is determined to bring to heel.

Mrs Clinton does not even seem to have an authoritative voice in dealing with the other regional trouble-spots of key strategic interest to her country: Iraq, which remains a quagmire for the US military, has effectively been left to Defence Secretary Robert Gates to deal with.

The same goes for Afghanistan and neighbouring Pakistan, where Taliban and Al-Qaeda types have taken refuge.

To make matters worse for Mrs Clinton, the Obama White House has appointed a bevy of “special envoys” for specific flashpoints who nominally should operate under the State Department but whose brief, the general consensus has it, is to answer to the White House.

For the Middle East, which has been a perennial, albeit self-induced headache for successive US administrations, Obama picked a distinguished retired senator, George Mitchell. Mitchell had previously mediated the Northern Ireland-British conflict during the Bill Clinton administration, with considerable success.

Mitchell’s stature in Washington is such that he might find deferring to the White House more natural than doing the same to the less experienced Mrs Clinton.

Iran is the other problem for the administration owing to its ongoing nuclear energy programme, which the US wants stopped.

So far, the Iranian authorities have spurned Obama’s overtures, but if they were to take them up, it is more or less a given that the White House would take charge of any deal-making on that front.

Neither has Mrs Clinton asserted herself on the other nuclear proliferation problem nagging the US — in North Korea. Again, the White House has assigned a special envoy for the task of coaxing that state to de-nuclearise.

The job involves getting Russia, China, Japan and South Korea together with the US into a united front, but so far Mrs Clinton’s footprint on this has not been very evident.

As if that were not enough, her husband, Bill Clinton, momentarily stole the US headlines from her Africa trip when he landed in North Korea and met the country’s reclusive leader, Kim Jong Il.

The stated purpose of the trip was to spring from jail two purported US journalists who had been imprisoned for illegally entering the country. The White House sought to describe the trip as “a purely private initiative.”

All said and done, there is a certain dynamic in the US at work which Mrs Clinton’s Africa trip underscored.

The fact that Obama is of African ancestry is not lost on his Cabinet officers. Any official engagement with these roots as the Secretary of State has just done is certainly not going to be shrugged off casually in present-day Washington DC.

But in the boiler-room of DC politics, Africa is probably not the corner where Mrs Clinton wants to be confined.