Building naval counterfactuals from contemporary arguments

Why not move farther back in time when proposing fixes for wartime navies?

Earlier changes are useful only when evidence shows what actors then could plausibly know, argue, fund, and build.

Useful counterfactuals begin with proposals and arguments available to people at the time. The exercise is to test whether a contemporary plan was viable and why decision-makers might have preferred it to its rivals. In 1939, the Admiralty's case for continuing carrier construction emphasized convoy protection, anti-submarine patrol, and detection of surface raiders. A stronger contemporary argument for carrier air defense might also have changed Churchill's response to the Royal Navy's fighter program.