If we simply follow the logic we laid out here, then the critics of unmanned aerial vehicle strikes have a weak case. It is not illegitimate to target individuals in a military force like the jihadist movement, and international law holds them responsible for collateral damage, not the United States. Moreover, respecting national sovereignty requires that a country's sovereignty be used to halt attacks against countries with which they are not at war. When a country cannot or will not take those steps, and people within their border pose a threat to the United States, the country has no basis for objecting to intelligence operations and airstrikes. The question, of course, is where this ends. Yemen or Mali might be one case, but the logic here does not preclude any country. Indeed, since al Qaeda tried in the past to operate in the United States itself, and its operatives might be in the United States, it logically follows that the United States could use unmanned aerial vehicles domestically as well. Citizenship is likewise no protection from attacks against a force hostile to the United States.
But within the United States, or countries like the United Kingdom, there are many other preferable means to neutralize jihadist threats. When the police or internal security forces can arrest jihadists plotting attacks, there quite simply is no need for airstrikes from unmanned aerial vehicles. They are tools to be used when a government cannot or will not take action to mitigate the threat.
The Strategic Drawback
There are two points I have been driving toward. The first is that the outrage at targeted killing is not, in my view, justified on moral or legal grounds. The second is that in using these techniques, the United States is on a slippery slope because of the basis on which it has chosen to wage war.
The United States has engaged an enemy that is dispersed across the globe. If the strategy is to go wherever the enemy is, then the war is limitless. It is also endless. The power of the jihadist movement is that it is diffuse. It does not need vast armies to be successful. Therefore, the destruction of some of its units will always result in their replacement. Quality might decline for a while but eventually will recover.
The enemy strategy is to draw the United States into an extended conflict that validates its narrative that the United States is permanently at war with Islam. It wants to force the United States to engage in as many countries as possible. From the U.S. point of view, unmanned aerial vehicles are the perfect weapon because they can attack the jihadist command structure without risk to ground forces. From the jihadist point of view as well, unmanned aerial vehicles are the perfect weapon because their efficiency allows the jihadists to lure the United States into other countries and, with sufficient manipulation, can increase the number of innocents who are killed.
In this sort of war, the problem of killing innocents is practical. It undermines the strategic effort. The argument that it is illegal is dubious, and to my mind, so is the argument that it is immoral. The argument that it is ineffective in achieving U.S. strategic goals of eliminating the threat of terrorist actions by jihadists is my point.
Unmanned aerial vehicles provide a highly efficient way to destroy key enemy targets with very little risk to personnel. But they also allow the enemy to draw the United States into additional theaters of operation because the means is so efficient and low cost. However, in the jihadists' estimate, the political cost to the United States is substantial. The broader the engagement, the greater the perception of U.S. hostility to Islam, the easier the recruitment until the jihadist forces reach a size that can't be dealt with by isolated airstrikes.
In warfare, enemies will try to get you to strike at what they least mind losing. The case against strikes by unmanned aerial vehicles is not that they are ineffective against specific targets but that the targets are not as vital as the United States thinks. The United States believes that the destruction of the leadership is the most efficient way to destroy the threat of the jihadist movement. In fact it only mitigates the threat while new leadership emerges. The strength of the jihadist movement is that it is global, sparse and dispersed. It does not provide a target whose destruction weakens the movement. However, the jihadist movement's weakness derives from its strength: It is limited in what it can do and where.
The problem of unmanned aerial vehicles is that they are so effective from the U.S. point of view that they have become the weapon of first resort. Thus, the United States is being drawn into operations in new areas with what appears to be little cost. In the long run, it is not clear that the cost is so little. A military strategy to defeat the jihadists is impossible. At its root, the real struggle against the jihadists is ideological, and that struggle simply cannot be won with Hellfire missiles. A strategy of mitigation using airstrikes is possible, but such a campaign must not become geographically limitless. Unmanned aerial vehicles lead to geographical limitlessness. That is their charm; that is their danger.