For smaller countries, asymmetric warfare is clearly of advantage. Smart (sea) mines, artificial barriers and obstacles (steel chains, spikes!), autonomous weap

For smaller countries, asymmetric warfare is clearly of advantage. Smart (sea) mines, artificial barriers and obstacles (steel chains, spikes!), autonomous weapon systems (drones), swarm weapons, EMC dischargers, mobile/portable weapon systems are things that can be mass-produced relatively cheaply, but could pose a significant defense against the advance of bigger adversaries. No one can win a war with air force alone, so there is always the need for troops on the ground. But the transportation of troops can be easily disrupted. Humans soldiers are precious asset but fragile. Killing or injure them on the sea, in the air and on the open land is much easier than taking and holding a city.