You're welcome, as always! Mahan's theory has been the basis for American naval power and was basically the same basis for British naval power, except they had/have a different guy. Mackinder, iirc, had the theory that political power coalesces in geographical "castles," which are large areas that support large populations, surrounded by terrain that makes a natural barrier, and the ultimate castle is Eurasia, and I might be conflating a few things, but iirc he called it "the world island" and whoever controls it is the master of the world. So British strategy has been to do anything to keep Eurasia fragmented, and the US' strategy has focused more on preventing anyone from becoming a regional hegemony - that's what's behind being all aggressive to Iran. The stuff about ideology is just for the headlines.