If war is indeed the continuation of politics by other means, talks should be as effective as bazookas in achieving the strategic objective. When to talk and when to fight, however, is one of the most vexed decisions that commanders have to make – as the recriminations over the British deal with the militia of al-Mahdi Army in Basra now make cruelly clear.

In the West, there is little tradition of negotiating while battles are in progress. Farther east, there appears to be little contradiction. In Afghanistan, tribesmen have long been adept at mounting an armed attack, breaking off to bargain over bribes and then resuming the attack if the price is not right.

The tradition in Iraq is less venal. But there is no doubting the cynicism of the Shia fighters entrenched in Iraq’s second city who launched continuous attacks on the 500 British troops in Basra palace to force them to accept a deal last summer: safe withdrawal to the airport in return for an accommodation with the Iranian-backed militia. British troops, it was understood, would no longer patrol Basra.

Whether this therefore ruled out support for the Iraqi Army’s attack on the militia in March is as unclear as it is contentious. The Ministry of Defence insists the reason that British Forces did not join the Americans in the first crucial week is because there was “no structure in place” for the troops to reenter the city. Angry Americans and Iraqis giver a harsher reason: Britain waited on the sidelines because of the deal.

With hindsight, it is clear that any deal dependent on a militia as unscrupulous as that controlled by Moqtada al-Sadr was likely to unravel. There were too many fighters driven by criminal motives to allow any hope that the accommodation would encourage al-Mahdi Army back into the political process or isolate the extremists. Instead British troops became party to a clique terrorising the city – a fact resented by its residents and by the Iraqi Government.

Hindsight, however, does not invalidate all military attempts to negotiate deals. Neither Iraq nor Afghanistan can be won by feats of arms alone. The Americans were adroit in winning over the Sunni tribal leadership in Anbar province in order to isolate al-Qaeda. Britain, in its long struggle with the IRA, has negotiated with political intermediaries even as the British Army was planning operations against the fighters.

The experience of Iraq and Afghanistan, however, makes two things clear. First, if force is the answer it must be used and deals can only be made with the right people and from a position of strength. The British arrangement to leave Musa Qala in Afghanistan two years ago was broken by the Taleban, who promptly returned in force. Secondly, any negotiation has to be part of a wider counter-insurgency strategy, consistently thought through and doggedly applied.

Here the Americans are at an advantage. Far from being the amateurs, out of depth in unfamiliar political terrain, as British critics patronis-ingly alleged at the start of both campaigns, US commanders are now thoroughly versed in local politics, adroit in negotiation and effective in hitting the right targets. Britain, by comparison, fields far smaller contingents in each country, with less equipment and more frequent rotations. It is a sensible, if belated, move to double British commanders’ tours in Afghanistan to a year, even if the troops spend only six months there.

The two wars are stretching British military resources to the limit. They should not, however, inhibit the will to fight, to devise effective strategy and to engage in appropriate talks. Basra was a bad deal, as the return of 900 troops to the city makes clear. It should not mark Britain’s future attempts to bring peace and stability to Iraq.