The Sunni-Shia split is fundamentally about dynastic versus elective succession

Evidence

At a very early date the famous split occurred between the Sunni and the Shi‘ite views, the Shi‘a doctrine being frankly dynastic. According to them, only the lineal descendants of the Prophet are entitled to rule as his successors. Since the Prophet had no descendants in the male line, a unique exception is made in favor of the descendants of his daughter, Fatima. The Sunni view, in contrast, as formerly set forth, was that the caliphate should be elective. This should not be understood in modern terms of universal suffrage. The juristic concept of election means that on the death of the caliph the most suitable successor is chosen by a small college of qualified electors. — Bernard Lewis, From Babel to Dragomans, 538

Categorization

• DEFINE: Clarifies that ‘election’ in Sunni juristic terms meant selection by a small college of qualified electors, not popular suffrage — a term often misread in modern contexts.
• XREF: connects to: The Sunni-Shi’a split originated from political succession struggles — Deepa Kumar, Islamophobia and the Politics of…, 317; The Sunni-Shi’a split originated from political succession struggle, not theology.