Were Napoleon and Alexander Blowing Bubbles

Napoleon's Empire at greatest extent (TheOtherSide.Com)

William Rosen, in his book Justinian's Flea, makes a comment to the effect that the cost to the Byzantine Empire of conquering and keeping the territories occupied by the Vandals in North Africa was not justified by their contribution to the Empire. The comment made me think about the economics of empires of conquest.

It seems to me that there are centripetal and centrifugal economic forces in these empires. City states gained in some ways from belonging to an empire, such as trade advantages and protection. They also paid not only in taxes but also in lost trading opportunities with other non-empire cities. The coercive empire added the threat of force to keep the empire together, even when the centrifugal forces would exceed the centripetal forces for some of the border cities.

The benefits from holding peripheral city states in the empire varied over time as productivity changed, populations waxed and waned, transportation costs changed, etc. So too did the costs of enforcing continued participation in the empire, as military technology changed, the power of externally threatening military forces changed, etc.

What I wondered was whether the military adventures of "the great conquerors" such as Alexander and Napoleon were not analogous to the housing bubble which we have just seen burst or the Dot Com bubble we saw burst a few years ago. In those bubbles the cost of possessions escalated beyond any justification from their future earnings or values due to a psychological failure to measure costs and potential benefits accurately.

So too Alexander and Napoleon represented social groups that invested more in conquest of extensive territories than they or their successors could hold, and their empires contracted rapidly from their largest extent. Surely each of these guys was capable of winning battles even when outnumbered, but each was also supplied with an army that was very large and well supplied for its epoch. Large numbers of supporters must have thought it worthwhile to invest resources in the enterprise of the conqueror.

Maybe these guys were more analogous to Bernie Madoff than hero geniuses.

Alexander's Empire at its greatest extent (Britanica online)