radius of action
The maximum distance a ship, aircraft, or vehicle can travel away from its base along a given course with normal combat load and return without refueling, allowing for all safety and operating factors.
Dictionary of Military and Associated Terms, US Department of Defense, 2005, p442
On the other hand, the phrase is also used to mean region of influence of a people or an army in terms of how far they can operate from home and still have a reliable supply line:
It's more of Inner Mongolia even if there was no such geographic concept (IM and OM) at that time, but Genghis Khan and his troops were mostly living and haunting in today Hetao district (in Inner Mongolia), northern Shanxi province and northern Hebei Province. However, you know, during the age of cold arms, a horse is like a tank, the Mongolian warriors had a very long radius of action, so it's not a problem if they planned to cross over the Gobi desert into the outer mongolian steppe/wasteland.
I am not sure that the latter usage is common in English. It's certainly present in historiography in the Hungarian language. (Apparently, military historian Géza Perjés claimed to have invented it.) My gut feeling is that this must have been first a technical term from military tactics for range and it acquired the strategic meaning only later because that is a more abstract concept.
What is the etymology of the phrase: when was it first used, with which meaning and in what context? Which language invented it first? (Cf. the German Aktionsradius in Duden.)
Oxford Dictionaries put its origin to the late 19th century but that's all I have found:
Late 19th century; earliest use found in The Times.