Drone wars

Why Drones Have Not Revolutionized War is a useful read. The authors conclude that drones don't "level the field" that much--the already powerful have the technology and training to leverage the tools better in attack and defense.

On the other hand... Some of the drone attacks on Russia have seemed to push the limits of how far drones can travel, and I've read speculation that some of the drones are launched and controlled from inside Russia. I'm not sure active drone control is a safe thing to do inside Russia, but fire and forget might work.

Damage to factories in the homeland, power lines, fuel depots, bridges--they can be as useful to your adversary as damage to your tanks, though the effect takes a little longer to percolate to the battlefield. They need to be able to supply their infiltrators, and provide training and up-to-date ways to counter your countermeasures.

Some countries would seem more vulnerable to this sort of attack than others: most obviously those with open borders and large foreign populations. Dispersed production is more resilient and harder to defend while centralized production, though you can concentrate your defenses, has more catastrophic consequences when attacks get through (as they will). I don't see how just-in-time systems could stand up to damage well.