The US spends billions on weapons, yet its fighters, helicopters, and ships date back to the '80s and '90s. Luckily, there's a precedent for the US overhauling its forces while cutting costs at the same time, writes Arthur Herman of the Wall Street Journal: World War II. Then, the US managed to jump from being the world's 18th-largest army to "a military second to none" in a slim five years—and "not because we spent a lot of money," he writes, "but because the dollars spent followed four simple business principles." Those being: