You don't need a sky full of drones to attack another country that has an army of drones. You need only a nuclear warhead delivered via cargo container to a strategic port by cargo ship.
That's just a scaremongering clishé, in reality you don't need anything other than good old TNT or a lot of magnesium to cut the ship in half.
Blow the port. You have just wrecked at least a digit percent of that nation's GDP, the cargo ship (net present value of its production capacity loss), especially if you can manage to get your container at the bottom of the stack, you disabled the port (if you blow it in a narrow place you cut off the port until they remove the wreck and/or dredge a new deep enough way).
And even if you don't achieve any of this, do it a few times and insurance premiums will rise considerably, people will be demanding "ACTION", and so on.
Of course, in a war, effective home propaganda can stifle these sentiments and you might be shooting yourself in the foot indirectly if you turn the civilian population against yourself.
