Gen David Petraeus is winging his way from Iraq to Central Command (Centcom), where he will oversee US military operations throughout the Middle East, Afghanistan and Pakistan.
He has to turn around the Nato mission in Afghanistan, where "the trends are in the wrong direction", he told me during an interview last week.
The general says he is giving much thought to how strategy towards Afghanistan and Pakistan - and the two countries are symbiotically linked - needs to be revised.
Since many in Washington credit him with rescuing the situation in Iraq - from one where insurgent attacks peaked at 180 per day in June 2007 to one where there are around 25 each day now - the pressure to find some new answers to the Afghan imbroglio is, to put it mildly, intense.
Gen Petraeus is also credited with revising US counter-insurgency doctrine, making its primary objective "securing the population".
This idea can be applied in Afghanistan. Indeed it can be argued that it already has been, with the alliance's adoption of an "ink spot" strategy of trying to create safe areas for pro-Afghan government people to live and operate.
The problem is, it hasn't worked yet.
So the Afghan situation begs the question: does the country need its own "surge", extra troops to allow the creation of larger "safe areas"?
Or will the historic hatred of foreigners exhibited by rural Pashtuns, the bedrock of Taleban support, simply mean that sending in more troops exacerbates the rural revolt?
Gen Petraeus spoke to Mark Urban on Newsnight
Another Iraqi approach that is already being used on a limited scale in Afghanistan but may be expanded there is the use of "Concerned Local Citizens" or Awakening Councils - a tactic that essentially consists of hiring gunmen away from the insurgency.
There are plenty of precedents for this in Afghanistan - and in fact the Soviet army had some success with this tactic in the 1980s - but Gen Petraeus will need to remember the old frontier saying that you can rent an Afghan but not buy him.
As for the areas of difference between the two conflicts, these are substantial and they begin at the most basic level with the way the Afghan campaign is being led; it violates military doctrine in that there is no true unity of command.
In Iraq the Americans have been in charge of security operations, with Iraqi troops under their control (until at least provinces are turned over to Iraqi control when the arrangement effectively flips).
President Bush's isolation over Iraq produced a situation where the wider world effectively said, "you're on your own", heightening the stakes for the administration, resulting in them taking virtually any step to avoid defeat.
Nobody "owns" Afghanistan in the same way. In some provinces operations (including Britain's) are carried on with a distinctive national flavour and an under-current of "we know what we're doing".
The war in Iraq is very different to that of Afghanistan
US forces are divided into a nationally commanded element and one run through Nato (although there are discussions about ending this).
The Afghan government of Hamid Karzai meanwhile remains convinced that it is in charge, despite the obvious limits of its capacity.
With Gen Petraeus taking over at Centcom, some Nato partners wobbling about keeping troops in Afghanistan and the US presidential election like to produce a new focus on the conflict there, one thing we can expect is for a clearer command structure to be established in 2009 with the Americans more obviously in charge.
The other key difference between the two campaigns will be even harder to address.
Iraq is expected to receive $80bn in oil revenues this year; Afghanistan's entire national government budget is less than $1bn.
Iraq is happily adding 72,000 soldiers to its army (currently around 300,000 strong) this year, while spending billions on new equipment.
So whereas there is a widespread acknowledgement of the need to build up Afghanistan's security forces, nobody knows quite how it will be paid for.
With this effort as with any Afghan "surge", we can expect Nato partners to talk a good game but contribute relatively little.
If Gen Petraeus wants major changes in this area as well, he will have to deploy his presentational skills on Capitol Hill once more, getting the United States to foot the bill.
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