By that reasoning, everything the USA has been involved in stems from "1866". Or various British Acts of Union led to two world wars. Or the Magna Carta, or the French Revolution, or anything before 1914 that involved any of the participants.
Furthermore, even if we un-ironically believe "1866" led to the US cavalry riding to everyone's rescue in two world wars, that is the end result, not setting the stage.
I know some people love to believe everything must revolve around the USA, but trying to argue that the two greatest events of the 20th century actually stemmed from 19th century internal American politics that meant relatively little to Europeans even at the time seems pretty desperate.
[1] Before anyone downvotes for this interpretation of what he wrote, he literally states the following simplistic, insulting garbage about WWI (where US involvement was barely more than symbolic): "[the USA] would intervene to defeat Germany just in the nick of time".
I wonder how he feels about the USSR intervening to defeat Japan just in the nick of time in WWII.
Absolutely. Obviously the Civil War did play a role (there's nothing in history that isn't connected in some way), but trying to set it up as a major cause of WW1+2? No thanks.
To me, the whole article seems to be the author trying to shoehorn history into his idea that the events of the year 1866 would somehow predestine the next half century. He brings up some interesting observations, but his main thesis doesn't hold water.