Dr Robert Crowcroft, Research Associate, UK Defence Forum

Almost certainly the biggest contemporary problem for the way in which the US and its allies wage war is our curious aversion to destroying and killing the enemy. The military power wielded by the US is so great that it is difficult to see how it can be 'defeated' in anything but the long term. Surely, you would think, that once battle has been joined the priority would be crushing the enemy, no matter how it is done. This trend is especially puzzling when we bear in mind that recent conflicts have been expeditionary operations and are, in effect, wars of choice: we have chosen to designate certain people as our enemies and make war against them.

The reticence about utilising our full strength to achieve our goals – goals which are apparently so important that we committed to war – is debilitating. Doing so for 'moral' reasons – in reality, merely the need for a socially unrepresentative group of politicians and commentators to feel themselves virtuous – only reduces the prospect of victory and, usually, constitutes no solution to the problem at hand. One important point here is that military behaviour appealing to the prejudices of the cosmopolitan classes hardly ever works and should be avoided like the plague. Another point centres on the unpalatable truth that killing the enemy and inflicting violence upon him is absolutely central to a successful war. It always has been. In the West, our sheltered societies have forgotten that. The contemporary expectation for wars to be virtually bloodless is simply pathetic and says a great deal – none of it good – about the state of our civilisation.

The fact is that there is no substitute for convincing an adversary of his defeat through graphic means; of shedding the enemy's blood in adequate quantities to achieve this; of showing resolution against opponents whose cultural background means that they only respect the clenched fist; and doing all this as quickly as possible once battle is joined. The modern aversion to inflicting, and sustaining, death in large quantities means that we no longer understand war for what it is: a matter of attrition, and of killing the opponent. War is brutal, and it must be so. Moreover, as Ralph Peters argued, attrition is 'not something to be avoided – and no rule says that attrition must be fairly distributed. The well-fought war inflicts catastrophic attrition on the enemy'. Only by sustaining heavy losses will the enemy be convinced of his defeat. Additionally, a few adversaries – like many Islamists – cannot be persuaded to desist no matter what we do; and so they must be killed.

Much of this reluctance to inflict harm stems from a laudable desire to make our enemies into friends. Yet the truth is that those who we fight will be alienated from us. We should not care too much what the enemy thinks of us. If relations can be improved, it is best achieved in the aftermath of a crushing defeat, by which the enemy is convinced of their powerlessness before us. Compare the mood of Germany in 1918 with that of 1945 for proof. In 1991, despite a battlefield hammering, Saddam Hussein could claim that he had 'won'. From his perspective this was true, because gangster regimes equate success with their own hold on power. Worried about being seen to be overly brutal, the Americans called off their assault on Saddam's fleeing forces. His regime survived.

Then, in 2003, the threats of 'shock and awe' were a bluff. The Sunni population, particularly, did not feel defeated by the US: large areas of the 'Sunni Triangle' in central Iraq did not even see American troops or vehicles for months. Because they had not tasted defeat and choked on their own blood, they were all-too willing to take up arms against us. This was repeated in 2004, when US threats to destroy the insurgents in Fallujah turned out to be another bluff. The Americans called off the operation midway through and allowed the enemy to remain in control, again being unwilling to stage a decisive show of force. The insurgents concluded that the US can be defeated by a show of resolve.

Winning wars against weaker opponents is not, therefore, a matter of strength, but will. The enemy must know the consequences of defiance, see those consequences around them, and remember them afterwards. President George W. Bush must bear ultimate responsibility for the mistakes made in Fallujah. Thankfully, to some extent he atoned for them by firmly imposing himself on the war in late 2006, and choosing to demonstrate US resolve. The consequences of the resultant 'surge' were impressive. The major lesson here should be this: why not put our shoulder to the wheel, and crush the adversary by doing whatever is necessary to inflict sufficient attrition and convince him of our will?

A similar, and compelling, case can be made for launching an attack on Iran – a prolonged and brutal campaign to degrade the power of the Iranian central state, destroy its military forces, and disrupt its nuclear programme would set Tehran back years. It will curb Iran's regional ambitions and appetite for interfering in Iraq and Afghanistan, as well as demonstrating US resolve more widely. Iran, after all, has de facto declared war on the United States more than once since 1979, to no adequate response. If we see the War on Terror as one of attrition, it is similarly difficult to come down against surgical drone strikes in places like Yemen and Somalia, targeted assassinations, or controversial measures such as intensive interrogation of combatants. These methods, applied over a long period of time, offer a route to victory. And if performed with resolution, they gradually make the problem smaller.

On 15 October, General David Petraeus announced that Special Forces have killed or captured 300 Taliban leaders in the last three months. Petraeus revealed that this represents an increase in the tempo of Special Forces strikes of perhaps three or four times the previous rate, and that many of the Taliban killed or captured were 'jackpot' figures. Translated, this means that they were key actors in the mechanics of the insurgency, both senior and mid-level militants. This followed from previous reports in September that American and British Special Forces are being used to kill Taliban on an 'industrial scale'. It has been suggested that at least a quarter of senior Taliban figures have been 'dealt with' since the spring of 2010, and that this has badly disrupted the Taliban war effort. Bomb-makers are among the priority targets; in consequence attacks from IEDs are down significantly, as are Western casualties.

The purpose here is to degrade the ability of the insurgents to operate by disrupting and decapitating; to deprive them of seasoned fighters – being a successful insurgent is hard, dangerous work and the skills must be accumulated over many years; and encourage the rest to negotiate a settlement by underlining the fact that they may soon be the ones with a bullet in the head. Meanwhile, the tonnage of bombs dropped on Taliban positions is now fifty percent higher than it was a year ago.

These methods indicate that the ISAF strategy, directed by the United States, has become harder and more ruthless. And this only reinforces the efforts of the ISAF forces in Afghanistan to secure the population by creating large 'security bubbles' around major towns and cities. If done properly, a 'counter-terrorism' strategy (finding and killing the enemy) can complement, rather than undermine, a 'counter-insurgency' policy (defeating the insurgency by securing the population; sometimes this involves not shooting back when attacked). It increases the incentives, both positive and negative, for the insurgents to put down their weapons. Official US counterinsurgency doctrine contends that in this kind of war 'advantage is best calculated... in terms of... which enemies are killed or detained' rather than simple numbers; 'key insurgent leaders' are the optimum targets. Moreover it argues that 'warfighting and policing are dynamically linked' – in some areas of Afghanistan the emphasis must be on policing, but in other areas, outside the major cities, it can be on hunting down and liquidating the enemy. This follows on from the Petraeus policy in Iraq, where population centres were secured while the insurgent networks were hit hard and gradually degraded or destroyed. Force must be employed smartly, but there is no substitute for the iron fist.

Bombing people one month, and hoping to be their friend the next, is therefore unrealistic and only signals weakness. Instead, the best way may be to grind the enemy into dust before extending the hand of friendship. If we opt not to overawe the enemy with our power, this only increases the likelihood of insurgency and prolonged occupation. In contrast, if we waged war in a punitive manner – defeat the enemy and clearly demonstrate our resolve – there will be less frequent need for nation-building. Why do we always need to rebuild a society ourselves? There is no moral imperative to do so. Let the adversary do it – after they have been crushed.

Leaving the enemy surrounded by the charred, smoking ruins of their cities will make more of a lasting impression than any amount of aid money; to put it bluntly, they will not want us to return and do it again. There is, then, a curious paradox at work here. The US and its allies are now uniquely averse to death in war. Yet no state matches the ability of America to inflict rapid defeat upon its enemies. Will it take a cataclysmic event to wake us from our slumber?

Robert Crowcroft is a Research Associate at the UK Defence Forum and a specialist on British politics and defence.