I've been reading Rothenburg's The Art of Warfare in the Age of Napoleon and Parker's Military Revolution: Military Innovation and the Rise of the West, 1500-1800, and while I realize there were a number of factors that played into Napoleon's eventual defeat (British economic strength/naval strength, ineptitude of Napoleon's siblings, guerrilla warfare in Spain), it seemed to me as I was reading that one strength of the Napoleonic army seemed to backfire horribly.
(Perhaps simplistic analysis ahead)
The army's ability to forgo food supply trains and live off the land (though the army had to split up to make use of this) gave Napoleonic armies their mobility (allowing Napoleon to pull off some amazing forced marches on his enemies), but at the same time, I wonder if this very tactic alienated otherwise friendly "host" countries and rulers - and perhaps Napoleon's defeat in Spain can partly be linked to this strategic practice (Russia's a can of worms that I'm not going to bother trying to analyse yet)
After all, a Spanish farmer can't be too happy about a bunch of French soldiers coming in and taking his food supposedly by order of King Joseph (José I). He might later join the resistance as a result! Is there any further reading on this subject or can someone who is more versed in Napoleonic diplomacy/strategy answer if there is such a direct connection between a fundamental Napoleonic era strategy and diplomatic/strategic repercussions?
EDIT: I did say this was a simplistic analysis, and perhaps I should have used Russia as an example after all - there are few campaigns that better illustrate the importance of logistics in warfare, and perhaps the argument can be made that the practice of foraging, which had served Napoleon well in central Europe, could not be applied in Russia (scorched earth tactics along with the naturally bad pickings from the environment). So Napoleon overstretched the logistical ability of his army, assuming he could move in the same fashion as he had in Italy more than a decade ago.