I think as many others have pointed out the decline of the US is focused on it's economic and political clout not military. Also I think your analysis of the Iraq and Afghan situation is just far too basic. There's a complex web of reasons why Iraq and Afghanistan might turn out to be a strategic failure (I say might cause there is still the possibility the Pentagon will get it's permanent military base in Iraq that it so desires).
Thing you have to remember is as a share of world trade the US has been in decline since pretty much post WWII after European and Japan centred economies started to take off. It went from 50% at the end of WWII to less than 25% today though it is far richer today then it was when it had half the words trade so it's no bad thing from a US point of view. The main difference now is it has to compete with very fast growing economies of countries who are very independent of the US. At least with Japan and Europe they were junior allies and still under the influence of the US so America had some leeway with those countries but with China and India and other members of BRICS it doesn't really have much say in how they run their internal affairs. South America has finally after 500 odd years of domination started to develop it's own independent path and we are seeing a wave of democratic uprisings in the Middle East that have either overthrown despotic rulers allied to the US or severely challenging those that are clinging to power. So economically and politically there is an evident decline.
Militarily the US is stretched no doubt about it and it's costing them a fortune. Though it's by far the most powerful nation on earth, it can't pressure everyone since some countries have nukes while others (inc those with nukes) have developed sophisticated asymmetrical tactics to somewhat offset the overwhelming conventional superiority of the US. It's a difficult catch 22 situation for the US since it's stuck between a rock and a hard place. If it draws down it's global military reach it will save an enormous amounts of money however it will also lose it's critical strategic leverage that it currently holds over it's industrial rivals.
However the US has been through severe crisis before and survived and it's competitors such as India and China have massive amounts of poverty which they need to address and huge internal problems of which the US has nothing like. We are talking about massive corruption, sometimes violent ethnic and religious tensions, major insurgencies, terrible environment degradation, lack of freedom and serious human rights issues. Just cause the US is going through a decline now doesn't mean to say it's a permanent one or that it's industrialised competitors won't suffer from economic issues at some point (cough*Japan*cough).
Btw why do you feel the BBC is anti-US? Do you say that because it's not pro US foreign policy enough like say Fox News? I think nowadays the BBC has moved more right after it was attacked for being too left liberal (like a lot the media really to be fair).
