LONDON -- If you're an imperial power, your troops often end up in places that most of your citizens cannot even find on the map: Mesopotamia for Roman soldiers, for example, or Afghanistan for the British. It looks foolish, viewed with the long perspective of history, and yet lots of people fall for it in the short run.

This week marks the 50th anniversary of the Suez crisis of 1956, when Britain, France and Israel conspired to invade Egypt. That operation took much less time to fall apart than the current Anglo-American invasion of Iraq, which has already lasted more than three years, but the parallels are irresistible.

The British-French-Israeli invasion of Egypt was an instant military success, because at that point Egypt had just emerged from centuries of colonial rule by the Turks and the British. Egypt was utterly incapable of defending itself against countries that had long-range bombers, aircraft carriers and amphibious forces. But what was striking, even then, was the sheer helplessness of the Anglo-French invasion forces once they had won their military victory.