Why was McClellan extremely cautious (U.S. Civil War)?

I know, and while I weould never argue things weren’t this way during said period…

(1) It didn’t, to my knowledge, affect Civil War startegy in any way, shape, or form. Napoleon, not Sir John Hawkwood and other condottieri, were the models under discussion, just as we don’t look a lot more closely to Vietname rather than what happened in 1610.

(2) It didn’t work so well for the Italian states, either, as Machiavelli points out.

I agree. War via maneuver requires both sides to be willing to abide by the same set of rules. If one side is willing to fight battles and the other side isn’t, the first side is going to win the war.

I can’t envision Lee writing to McClellan in the summer of 1862 and saying “You’ve totally outflanked my position on the James River. No sense on any further bloodshed. I’ll agree to withdraw into the Carolinas and let you have Virginia.”

And yet it’s not too hard to imagine McClellan writing such a note…

It’s not just that - it’s the difference between limited war and total war. So long as the North was determined to dissolve the CSA, limited war was not an option. And you can’t win total war by maneuver, because the best maneuver can achieve is concessions, not surrender - or annihilation.