Prof. John Mearsheimer: The only place where you have something of a balance in terms of firepower up on the frontlines has to do with drones. These drones have played a key role in allowing the Ukrainians to compensate for the fact that they don't have enough troops to cover the front line. Without drones, both the balance of firepower and the balance of manpower is so lopsided in Russia's favor that I think the Russians would have rolled up the Ukrainians a year or two ago.