By James Landale
BBC News chief political correspondent, Afghanistan
For Gordon Brown, the summer of controversy has pushed Afghanistan to the top of his in-tray.
The sheer scale of the British deaths - 38 since the beginning of July - and the rows over possible helicopter shortages have brought the war centre stage at Westminster in a way it has not been for some time.
And the questions that are being asked by the British public are being felt in Downing Street.
So this is one of the reasons why Mr Brown is here sweating with the rest of us in the midday Helmand sun, talking to troops and examining military vehicles.
This is his fourth visit to Afghanistan in the last year, proof, he believes, of his commitment to the conflict and the work of British forces.
But since the prime minister was last here in April, public anxiety has grown over casualties and equipment and the uncertainties over the election.
Case for war
So Gordon Brown came here not just to show his support for British troops but to restate his case for war, the need in his view to tackle a terrorist threat that, if unchecked, could reach the streets of Britain.
His more subtle task is to prepare the way for more British troops coming to this hot desert.
A crucial job for some of the 9,000 British forces here is training up Afghan troops so they can hold ground taken by coalition security forces.
There are currently some 80,000 to 90,000 Afghan soldiers. There were plans for another 50,000 to be trained by the end of 2011. The PM wants that brought forward by a year to November 2010.
But for that to happen, more British forces will be needed to train, mentor and partner all those new Afghan troops.
It is this that he discussed with General Stanley McChrystal, the American head of US and Nato forces here.
He is expected to recommend to President Obama shortly that more troops be sent to Afghanistan. What he says will have a huge impact on the scale of any British troop increase.
As part of his implicit case for raising troop numbers, the prime minister is also promising greater action to combat the threat of improvised explosive devices, which are responsible for three quarters of coalition deaths in Afghanistan.
So he has said that another 200 anti-IED specialists will be deployed in the autumn and there will be more unmanned surveillance drones and better protected vehicles.
The problem for the prime minister is that so much of this conflict is beyond his control. How much of the ground taken from the Taliban during the recent Panther's Claw operation will remain held by Afghan forces?
Just how many extra troops will the Americans ask for? Just how legitimate will the new government in Kabul be?
And perhaps most important to people at home, will the new efforts against IEDs actually work? All questions for which as yet there are no answers.