How hard is it to run the Pentagon?

“SO VAST IS the [Department of Defence] and so multifarious are its missions,” wrote Ash Carter, America’s 25th secretary of defence, “that it dwarfs most institutions on Earth.” The Pentagon owns or maintains almost 30m acres of property, he noted, an area larger than Pennsylvania. Its carbon emissions are about 1% of the country’s total. Its annual budget, a little over $800bn, exceeds the GDP of Taiwan, Belgium or Argentina.