For the last century, since the rise of mechanised and then nuclear warfare, defence budgets are designed to stop big existential attacks. Ships, planes, submarines. But cheap, retail store level technology - drones - have changed the game in the conflicts involving Ukraine and Israel. There’s no real way to immunise against a drone swarm that’s been smuggled into your country and hidden in a truck. These covert attacks are relatively cheap to deploy and incredibly effective. Like the nuclear bomb, the machine gun, and the crossbow - drones mean the traditional way we fight wars is finished.