by September 1940

U.S. coasts seemed as vulnerable 62 years ago as they suddenly seemed after September 11. Today the threat is understood to be hidden-bombs or terrorists arriving in container ships-but then fear centered around a naval assault. Batteries of 16- and 12-inch guns were built near principal harbors, but mostly went unused. Where they might have been tested, at Pearl Harbor, they were silent, ineffective against the surprise aerial attack.

(Left: The concept

of umbrella coastal defense– placing large weaponry near presumed major entry points–took a beating

in the Pacific Theater. When Japan invaded the Philippines, troops landed

well north of the major gun batteries at Manila, avoiding