•Why it earns a slot
The essay that turned faction from a bug into a design constraint. Every argument about polarization still runs on its rails.
Factions are inevitable because liberty produces them, so a constitution must control their effects rather than remove their causes. Madison's answer: a large republic, where representation and sheer scale make it hard for any faction to capture the whole.
This distillation is written from the freely available original, which is always the better read when you have the time: avalon.law.yale.edu.