Endurance as a treaty-cruiser design tradeoff

Should endurance and range be treated as a fourth corner of the treaty-cruiser design triangle?

Yes, but its importance depends heavily on each navy's geography, bases, and intended operations.

Endurance belongs in the familiar speed-armament-protection trade space, but its weight varies by navy. Range matters according to where a ship is expected to operate and which routes it must cover. Italian cruisers could trade endurance for other qualities inside the Mediterranean, while British ships could draw on an imperial base network. American and Japanese cruisers faced different distances and approach routes across the Pacific and South China Sea. The same numerical range can be adequate for one navy and a serious constraint for another.