London Treaty pressure and the Portland shift

The treaty discussion criticizes the First London settlement as a politically driven attempt to control naval competition, then carries that criticism into the Second London talks, where naval personnel were excluded. It also rejects the idea that a naval arms race alone caused World War I. Against that background, the U.S. Navy began moving away from the pure scout-cruiser logic of the earliest treaty ships. Japanese plans to place eight-inch cruisers near the battle line made the lightly protected American scouts more likely to meet opponents they had not been designed to fight. The Portland answer was to give up a gun, use three triple turrets, and spend the saved weight on a modest increase in armour. In this assessment, a Pacific war fought in the 1920s would have made the Pensacola, Northampton, and Portland classes appear far more successful because the conditions would have matched their intended scouting employment. The result still belonged to a reconnaissance tradition, but U.S. cruiser design was already adapting to a more dangerous surface-fighting environment.