Air strikes point to new US strategy to save troops: Patrick Cockburn in Washington says the Pentagon has learned from Vietnam and Lebanon

THE AIR attacks in Mogadishu and Baghdad over the last two weeks show a new trend in United States intervention abroad, whereby the headquarters buildings of hostile forces are targeted but no ground troops committed. This limits the risk of US casualties and avoids comparisons with US intervention in Lebanon in 1982-84 or Vietnam at an earlier date.

A UN spokesman said the villa attacked by 17 US helicopters in southern Mogadishu was a command-and- control centre for Mohamed Farah Aideed's militia. The impression was of a miniature Pentagon, the destruction of which would weaken Gen Aideed. Two weeks earlier, US spokesmen said the 23 missiles fired at the Iraqi intelligence headquarters in Baghdad had 'crippled' Saddam Hussein's intelligence operations.

Although the air strike in Mogadishu was nominally carried out by the UN, the decision to take a hard line against Gen Aideed was essentially American. The UN envoy is Jonathan Howe, recently retired from the US navy, and the Turkish UN military commander was reputedly handpicked by the US.

For President Clinton the advantage of these air attacks is that they show US strength without endangering US troops. The White House and the Pentagon are acutely conscious that involvement in Beirut led to 242 US marines being blown up, and a humiliating withdrawal.

Belief in the power and accuracy of 'surgical air strikes' is a legacy of the Gulf war. Television pictures of smart bombs and Tomahawk missiles slamming into Iraqi buildings seemed proof that air power could strike with the pin-point accuracy which it had promised but failed to deliver in the Second World War and Vietnam.

Missiles and smart bombs can hit large stationary targets from a long distance, but the US air force is less candid about the limits of this ability. The target must be easily identifiable and not mobile. It is therefore easy to hit power stations and refineries. Against an intelligence organisation or a militia, both dependent on people not equipment, the accuracy counts for little.

Air power in the Gulf war was actually less effective than claimed at the time. A vital target for allied air power were the mobile Scud launchers used to fire ground-to-ground missiles at Israel and Saudi Arabia were a vital target for allied air power. During the war allied aircraft claimed to have destroyed 80 of the launchers in 1,500 strikes.

But an independent survey for the air force published this year showed that allied aircraft failed to hit any Scud launchers. The report says the targets destroyed were largely decoys or fuel trucks. It says that on 30 January 1991, the US Central Command showed a video shot by an F-15E hunting for Scuds as evidence of success. It says: 'While it was confidently asserted on this occasion that at least three - and possibly seven - of the vehicles in question were mobile launchers, it appears far more likely that the objects were in fact commercial fuel trucks.'

Investigators said of 163 abandoned or destroyed Iraqi tanks only 10 to 20 per cent were hit by air-delivered munitions. About half had been abandoned by their crews and were not damaged. Attacking the intelligence headquarters is unlikely to have much impact. The same is true of Gen Aideed's militia, which is not dependent on fixed installations.

The withdrawal of 2,200 US Marines and four AC-130 gunships from Somalia announced yesterday may indicate that Washington realises it cannot control Mogadishu by air power alone. The lack of US casualties means there is little controversy in the US about the attack on the villa, but the UN has become bogged down in the quagmire former President George Bush promised would not happen when he sent in the troops last December.