The last line of A Separate Peace is as follows:
All of them, all except Phineas, constructed at infinite cost to themselves these Maginot Lines against this enemy they thought they saw across the frontier, this enemy who never attacked that way—if he ever attacked at all; if he was indeed the enemy.
Knowles makes an explicit connection in the last line between the seeds of hatred and conflict being planted in individuals and larger conflicts, such as World War II. He argues in the paragraph before this last line that we end up with wars, both personally and collectively, because we create enemies and then cut ourselves off from them or fight to defend ourselves against them.
To understand the quote, one needs to know what the real Maginot Line was. It was a vastly expensive series of well-equipped trenches and concrete walls built by the French in the 1930s to repel a German attack. The French believed that it was impervious to attack and that the Germans could never get around it. It is...
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