On guerrilla warfare:

1. I was in Afghanistan in 2002. I remember well the hulks of the Soviet vehicles, rusting and bleaching in the sun. Anyone that doesn't think an asymmetric, small, less hierarchical force can't eject one with more firepower could stand to read about the last 250 years of Afghan history. They tossed the Brits, the Soviets, and now the US. Or if you need one more data point go back to Alexander the Great's era.

2. The term "guerrilla" was coined in what is actually, by my measure, the excursion that was Napoleon's second biggest defeat and the most worthy of study. His #1 defeat was naturally his incursion into Russia, where he was overextended, culminated, and came back to France with maybe 5-10% of the combat power from which he started with. Guerrilla came from the era when he invaded Spain. The Basque region's folks didn't take too kindly to this - and naturally even today Spain lets them do their own thing to a large degree - and over several years they whittled and ankle-bit his forces down to where they left, reasonably broke and dejected. Napoleon called it the fatal knot. There's a book called The Fatal Knot about this.

3. What we're watching today is a master class in lithe, adaptable forces smacking the snot out of a bigger, more kitted out, more linear force. The revolution in drones is so impressive that I wonder if we can ever have a functional Armor branch in the Army again, given their high lethality and low cost.