TIL, the U.S is considered by many military experts to be entirely un-invadable due to country's large size, infrastructure, diverse geography and climate : todayilearned: ""Shall we expect some transatlantic military giant, to step the Ocean, and crush us at a blow? Never!--All the armies of Europe, Asia and Africa combined, with all the treasure of the earth (our own excepted) in their military chest; with a Buonaparte for a commander, could not by force, take a drink from the Ohio, or make a track on the Blue Ridge, in a trial of a thousand years.
At what point then is the approach of danger to be expected? I answer, if it ever reach us, it must spring up amongst us. It cannot come from abroad. If destruction be our lot, we must ourselves be its author and finisher. As a nation of freemen, we must live through all time, or die by suicide."--Abraham Lincoln, 1838"
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