The Great Equalizer

Forget the Colt-45 "Peacemaker" -- the great equalizer is the RPG-29.

One of the factors in Hezbollah's victory on points against the Israeli Defence Force last year was the humble rocket propelled grenade. The RPG is not your grandfather's bazooka: the (former) Soviet-made RPG-29 Vampir was specifically designed to defeat reactive armour. It uses two shaped charges, the first to trigger the reactive armour and the second to blow a hole through the tank. Costing around $500 for the launcher and $250 per missile, the RPG-29 was impressively effective at destroying the Israeli Merkava tank, reportedly the most heavily armoured tank in the world. That makes the RPG-29 one of the most impressive giant killers out there.

This suggests that the overwhelming advantage of First World armies with their heavy tanks costing millions of dollars could be severely undermined. This will make the cost of invasion far higher, both in soldiers' lives and dollars, and allow infantry to go toe-to-toe with heavy armour. If true, that's probably the biggest shift in military technology since the invention of the pike formation which allowed infantry to defeat armoured knights.