Things (CIRCA 1541)
Of course, we Americans knew that, felt it in our marrow as we marched raucously across a continent. Historian Frederick Jackson Turner explained it to us in 1893, when he wrote of the closing of our Western frontier. "What the Mediterranean Sea was to the Greeks, breaking the bond of custom, offering new experiences, calling out new institutions and activities, that, and more, the ever retreating frontier has been to the United States."
At about the same time, Admiral Alfred Thayer Mahan explained, without saying it in so many words, that this nation's new frontier had to be...