County-class cruisers and a qualitative Anglo-American race

How much alarm did the County class cause in the US Navy?

Very little; the Americans answered with ships for their own scouting doctrine rather than treating the County class as an immediate threat.

The Royal Navy preferred a balanced eight-gun cruiser, while the US Navy emphasized a nine-gun scout; each built for its own operational needs. This was a qualitative competition driven by pride and design preference, rather than the dangerous quantitative buildup that signals fear and can push powers toward conflict.