Why do Historians sigh when they hear the words "But this is what I was taught at school"

A school history course must reduce large subjects to teachable pieces, even when its teachers know the subject well.

Before World War I, factions within the same country could press for war while others resisted it, which makes a state difficult to treat as a single actor.

A World War I example shows why a single factor can trouble one power while also serving another of its strategic interests.

School provides a foundation, but understanding historical causes more fully requires continued reading beyond examinations.