A current story in The New Republic highlights a major theme in the LGS textbook: History Matters. The fancy term is "path dependency" which they define as "the idea that certain possibilities are made more or less likely because of the historical path take."
Here's the nutshell story, it involves the transition from the Nixon to the Ford Administration necessitated by Watergate:
"On a limousine ride from his Virginia home to the White House, Ford considers their list of candidates to lead the transition. The aides suggest Frank Carlucci, then undersecretary of health, education, and welfare. Their alternates include Deputy Defense Secretary William Clements and NATO Ambassador Donald Rumsfeld. In the blank space on the page, Ford writes in Rumsfeld's name. ...
What if Ford's pen had scrawled out a different name as the car crossed the Potomac? No transition-chief Rumsfeld means no Chief of Staff Rumsfeld. Which means no chance to tap an unknown Dick Cheney as his deputy, no chance for the men to form their lasting bond, no chance for Cheney to take over upon Rumsfeld's departure. And on and on down the road to Baghdad: No Chief of Staff Cheney means no Representative Cheney, which means no Defense Secretary Cheney, no vice-presidential selection team leader Cheney, and no Vice President Cheney to bring his old mentor back to Washington a couple of decades later."
The author might have gone back even further. What if events had not led to the decision to break into the Democrat's headquarters in the Watergate building?
Or if the burglars had not been caught? Apparently they were found out because a guard on duty noticed tape on an exterior door which prevented the door from locking. He followed his nose, found the men, and history began taking a turn.
One could also argue that an unstable, oil rich Middle East would have inevitable drawn us in, but in a different manner, with different players and perhaps different results.
Fun to think about over beer and pizza.
By the way, the person most noted for developing this idea to explain economic development is Douglass North and it won him a Nobel Prize.