How was the British invasion into the US successful in the War of 1812?
My friend and I are from Britain and we were discussing which country was the least likely to ever see a successful invasion attempt. We reached the conclusion that the United States was simply the most difficult. There are two oceans on either side, with a navy unparalleled, and an airforce equally incomparable, massive swaths of difficult terrain to the north and south, and hundreds of millions of guns in the hands of citizens, militias, and very large gangs.
Because we reached this conclusion, we started wondering how the British were successful in the War of 1812.
Now, I'm not completely ahistoric here, as I know the United States had an extremely small force of men to defend themselves while we were an unimaginably large empire; but, nevertheless, I cannot imagine that it simply comes down to superior military numbers and equipment. How did they handle the mostly uninhabited terrain, and the native tribes bombarding them? And how was this feasible at all given that they were at war with France?