Built to be impenetrable, the Maginot Line was France’s answer to future invasions—an immense fortress stretching across its eastern border. But when WWII came, it faced a very different kind of enemy ...

Gaps in defences are always designed to be covered by overlapping positions, with defences in depth to create a broad and deep defensive line. 30,000 Russians is no gap in any defence.

is to be ready to hurt the enemy more than he can hurt the U.S. “A Maginot Line on the ground is bad enough,” said one Air Force officer last week. “There isn’t any line you can hold in ...