The attack was designed to make Saddam Hussein think again about violating United Nations Resolutions by knocking out some elements of Iraqi military power rebuilt since the Gulf war, which began almost two years ago. But it was directed mainly against targets and equipment involved in recent violations of those resolutions - 'proportional response' to accumulated Iraqi violations.
It is impossible to compare the two sides in the latest military contest as their forces are completely different in nature. In the Gulf war, both had large armies of about half a million facing each other when the air war started. Iraq now has up to 50,000 men in the south of the country, mainly infantry surrounding Shia rebels in the southern marshes. Some military sources suggest there is up to a division of Iranians helping the Marsh Arabs, tying down most of the Iraqi troops in the area.
The US has few ground forces in the area: 1,600, out of a total presence of 17,000. A tank battalion has been training in Kuwait. But the strike, which witnesses say began with aircraft taking off about 7pm local (4pm GMT) was exclusively from the air.
The US, Britain and France have about 200 aircraft in the area, and all seem to have been involved, including six British Tornado GR1 bombers and eight French Mirage fighters.
Up to 80 US combat aircraft were on board the carrier Kitty Hawk: the rest at Dhahran or, in the case of the F-117 stealth fighters, Khamis Mushayt, both in Saudi Arabia. Awacs command aircraft and airborne tankers would have been on station flying elliptical paths just south of the Iraqi border.
First reports confirmed the allied aircraft had not attacked Baghdad, but concentrated on radars and missiles elsewhere, and that the assault was led by F-117a stealth fighters.
The first principle of war is 'selection and maintenance of the aim', and some analysts have said the aim should now be to unseat President Saddam. This would mean targeting those facilities and institutions keeping him in power - command bunkers, secret- police barracks, communications headquarters - many of them in or near Baghdad.
Attacking Baghdad is politically risky, not least because of the probability of civilian casualties and the possibility of downed pilots being captured. It would be a high-risk strategy and unless carried out with overwhelming force, unlikely to achieve the corresponding high gains.
A more limited aim, destroying the surface-to-air missiles and supporting infrastructure, and possibly an airfield or two near the no-fly zone south of the 32nd parallel, was therefore preferred. To do that, the allies had to paralyse the air-defence network in the area. This may have included attacking the command and control centres near Basra.
The allies may also attack facilities near Umm Qasr, where Iraq has been recovering arms from the Kuwaiti side of the border. Such an attack would be punishment fitting Iraq's perceived crimes.
The Iraqi airfields are huge - many bigger than London's Heathrow. The British air commander in the Gulf war, Air Vice- Marshal Sir William Wratten, gave up attempts to close them, especially when it became clear the Iraqi aircraft posed no real threat. But if one or two airfields were selected, aircraft in hardened shelters could be destroyed individually. Iraq has between 300 and 350 combat aircraft although there are probably fewer pilots and aircraft in a condition to fly.
The SA-2 and SA-3 missiles are antiquated - they entered Soviet service in 1957 and 1961, respectively. In the last few days Iraq has moved them into the no-fly zones south of the 32nd parallel and north of the 36th. It will be easy to destroy them, but they would not be much of a loss.
If the SA-2 and SA-3 anti-aircraft missiles south of the 32nd parallel were supposed to be a threat to allied planes over the no- fly zone, why were the planes able to attack and destroy them yesterday and return unscathed? The Iraqi missiles were never much of a threat - General Colin Powell, the US Chief of Staff said so recently. But they would be more dangerous against jets pursuing other targets than when directly attacked. The allies launched a massed onslaught against them with electronic suppression measures. The attack also dismantled the command and control system linking the missiles.
Intelligence sources confirm that since the Gulf war Iraq's military strength has been rebuilt to about 40 per cent of pre-war levels: to an army of 350,000 men and about 2,000 tanks and artillery pieces. At the beginning of the Gulf crisis in 1990, Gen Powell, said it might be desrirable to reduce Iraq's strength to about 100,000 troops and 100 tanks - an aim that was not achieved.
During the war Iraq's centralised air defence network was destroyed but may have been rebuilt to a limited extent. Intelligence sources say they expect the Iraqis to be able to put up some opposition to an air attack using radars which survived the Gulf war or which have been repaired.
In the 1991 war, Iraq inflicted most damage to allied planes with anti-aircraft guns. In last night's attack the allied planes would have been able to strike from above the guns' ceiling. The Lockheed F-117 was one of the outstanding aircraft of the last Gulf war. It was the only plane allowed to fly over metropolitan Baghdad and, being virtually undetectable by radar, did not suffer a scratch.