I think that the best answer is the geographic location: many other countries (Sweden for example) have tried being neutral at different times but did not manage to: but the fact that the US has only two boundaries, and that both other countries also have a history of fighting from independence from a European power, makes it possible that unless US decideds to get involved in international politics, it can be "left alone".
They sent troops over to China to subdue them
The boll weevil made it hard to grow cotton (one of the biggest crops in the south) and made decimated the cotton industry
the road ended in vandalia, Illinois
