text: But his killing in an air strike is a grievous strategic error - militarily insignificant but diplomatically disastrous.
  Towards the end of April, Nato states made a number of operational innovations. Three member states - Britain, France, and Italy - injected military advisers into rebel-held eastern Libya. Another, the US, began continuous patrols of armed drones.
  Third, and most important, air strikes began to target command, control, communications and intelligence networks (known, in military parlance, as C3I). The Bab al-Aziziya compound includes all three such networks, and it was presumed that their disruption would disorient regime soldiers on the front line, cut off field commanders from Tripoli, and sow confusion in the ranks.
  But was the strike also an assassination attempt?
  Assassination of a head of state is illegal under international law, and forbidden by various US presidential orders. On the other hand, the targeted killing of those woven into the enemy chain of command is shrouded in legal ambiguity.
  Given the personalistic nature of the regime, and the "all means necessary" clause in UN Resolution 1973, it might be argued that killing Col Muammar Gaddafi and certain members of his family - such as his son Khamis, commander of an elite military brigade - would be permissible, even if it posed a risk to those non-combatants around the regime.
  Legality, though, indicates neither legitimacy nor prudence. This strike, and the death of Saif al-Arab, have produced little military result at the greatest diplomatic and symbolic cost to Nato.
  Saif al-Arab was, unlike his brothers, not a senior military commander or propagandist. His death is redolent of the 1986 US strike on the same compound.
  That raid killed a girl who Col Gaddafi later claimed was his adopted daughter and, in the scarred buildings and craters, furnished him with a long-lasting symbol of defiance.
  The propaganda value of such unintended deaths is potentially severe.
  In the 1991 Gulf War, a US stealth bomber directed two bombs at what was claimed to be a command-and-control bunker, but was in fact an Iraqi civilian shelter.
  The result was 315 deaths, including 130 children. Col Gaddafi, like Saddam Hussein before him, will take every opportunity to exploit such errors to paint Western powers as indiscriminate aggressors.
  Moreover, this is no longer a conventional war in which top-down direction is crucial. Pro-Gaddafi forces in both the besieged western city of Misrata and in the east have adapted to Nato's air power and are using increasingly unorthodox tactics.
  They need not rely on a stream of detailed orders from Tripoli, and can cause considerable harm to civilians without this guidance.
  Nato is understandably frustrated at the diminishing returns of air strikes, since it has destroyed most accessible targets. But killing commanders and disrupting communications is far less important than the key task of degrading heavy military equipment, such as tanks and artillery.
  If the strike had killed Col Gaddafi himself, would it then have been at least a military success?
  One of the greatest mistakes of the Iraq war was assuming that, with the departure of Saddam Hussein, the state apparatus could simply be transferred to new ownership.
  Col Gaddafi's death could see Saif al-Islam Gaddafi take the reins, galvanise supporters, and continue the war with equal intensity. It would be dangerous and short-sighted to portray even effective assassination as a silver bullet.
  Perhaps, though, the demonstration to the regime that no safe haven exists, and that only capitulation would bring security, justified these risks?
  There is no doubt that, along with the military aim of disrupting command-and-control hubs, Nato sought a psychological effect, conscious of the possibility of "accidental assassination".
  The problem is that the direction of this effect is unclear. The dramatic visual impact of this air strike, and the death of those disconnected from political and military leadership, will harden the diplomatic opposition to the war, from Russia and China amongst others.
  More consequentially, it will anger the alliance's warier members, like Germany and Turkey, and inflame parts of Arab and African public opinion.
  It may eventually leave Britain and France bearing the military burden alone, with modest but limited assistance from a cagey US administration eager to keep at arm's length from this European war.
  Col Gaddafi's overarching strategy has never been to win a conventional war, but to induce symbolically prominent casualties, drive a wedge between more committed and more ambivalent members of the coalition, and knock away the pillars of political support on which this intervention was built.
  Thus far, the coalition had sought, rightly, to purchase coalition longevity at the price of campaign intensity. If that balance continues to shift towards the latter, Nato runs the risk of playing into the regime's hands.
  Shashank Joshi is an Associate Fellow at the Royal United Services Institute (RUSI), a defence think-tank in London, and a doctoral student of international relations at Harvard University.
target: The death of Saif al-Arab Gaddafi, if confirmed, is likely to have come as a consequence of Nato's increasingly aggressive tactics, undertaken by the alliance to shake up a stalemate in the conflict.