The outstanding politico-military lesson is an old one: that one clarify one's aim before one embarks upon a military operation; ruthlessly and objectively dissect and analyse where it will lead, what is to be gained from it, and what one will be faced with when it is over.
The Suez affair is the supreme example of failure to subject policy to such an examination.
At a time of national emotion, like 1956, clear thinking in public, government or even general staffs can be obscured by anger, jingoism and pride - national and personal. Would bin Laden have emerged if the above process had been applied to the decision to support him and the Taliban, if there was such a decision?
So far, despite anger and his powerful forces, President Bush has kept his cool, listened to balanced advisors and brought the American people with him. No doubt the Pentagon and State Department have worked on the aims and their formulation. We should not expect to be made privy to all their thoughts as yet.
One formulation has caused comment - creating conditions that would allow the Northern Alliance to dislodge the Taliban.
The Observer said yesterday that "senior sources in Whitehall consider that the Northern Alliance is unfit to form a government and will not get backing from Britain". Disagreement on fundamental aims is dangerous, although this one may not be official.
The same report claimed that the Taliban leadership will be the "centre of gravity" of the allied attack. This may have been a general remark, without any wide overtones but the term has a technical military meaning.
Clausewitz, the great 18th-19th century writer on war, still has relevance, as Vietnam showed. An enemy's "centre of gravity" is "the hub of all power and movement on which everything depends . . . the point against which all energies should be directed".
In some cases this centre is the army. If the army of Alexander the Great, for instance, had been destroyed he would have been a complete failure.
In countries of domestic strife, it is the capital. In small countries, relying on large ones, it is usually the army of their protector. In alliances, it lies in the community of interest, etc.
If bin Laden and the Taliban leadership are destroyed, will Afghanistan and terrorism fall apart? One wonders.
What weapons are in Afghanistan? I say "in Afghanistan" because reliable sources agree with the military balance issued by the International Institute for Strategic Studies that "it is impossible to show the division of ground force equipment among the different factions".
Instead, the weapons known to be in the country in 1992 are listed. Subsequent deliveries are unknown:
A thousand Soviet "main battle tanks" are shown - T54s, T55s and T-62s. The former are long obsolete and only usable against similar ones. The latter are more recent.
A thousand armoured personnel carriers of various types - a spares nightmare, if many have survived.
Unknown quantities of Soviet artillery, 76 to 152 mm calibre, including the rugged ubiquitous 122 mm types, so familiar in the Middle East.
There are about 20-30 Scud and Frog missiles, some multiple rocket launchers and various air defence (AA) guns.
There were 115 SA-2 and 110 SA-3 air defence missiles. An SA-2 (31 miles range) brought down Gary Powers in 1960. The SA-3 covered 18.5 miles. Some updates were done by the Soviets but they were eventually replaced. Good missiles in their day - but can they still be launched?