The U.S. should have been at the top of your list. Thousand-mile moats to east and west, forests to the north, deserts to the south. Lots of very productive agricultural land, most near inland waterways. Not reliant on imports for food, energy, or most industrial products. Not reliant on exports to keep economy functioning. Navy a multiple of all other nations navies combined (mostly because it can afford to do that - see above for why). Closely allied with the U.K. and Japan (both major naval powers). The list goes on...