How navies defined the destroyer leader differently

What was the thinking behind American destroyer leaders such as Porter and Somers, and were they uniquely American?

Many navies used leaders. The American concept emphasized leading destroyers, while British and Japanese examples reflected different mission priorities.

Destroyer leaders were used by several navies, with different ideas about what the ships should do. American leaders are described as ships intended to lead destroyer formations. British leaders are characterized as taking on cruiser-like work, while the Japanese concept emphasizes a large torpedo armament. The single-purpose guns on the American examples are judged adequate to their intended work at the time. The label therefore does not by itself determine one armament or tactical role.