The U.S. uses $4 million Patriot interceptors to destroy drones that cost $20,000 to $50,000.
The war in Iran teaches an old lesson about military spending.

Six hundred years ago, on a muddy field near Agincourt in northern France, King Henry V’s outnumbered, half-starved English army faced the flower of French chivalry. French knights were expensive, each man-at-arms the product of many years of training, his armor and warhorse a major investment.