How did Cosimo de’ Medici manipulate Florence’s system for choosing public officials?

Cosimo de’ Medici maintained the appearance of a constitutional regime in Florence while effectively consolidating power by manipulating the city's electoral processes. Although he did not alter the administration of the law, he fundamentally changed its spirit to ensure his control.1

Previously, high official positions were filled by drawing lots. Cosimo manipulated this system so that the names drawn were exclusively those of individuals he could depend upon. Furthermore, he neutralized the independent influence of the municipal assemblies by making an exceptional procedure the rule: he ensured that dictatorial powers were granted for fixed terms that were consistently renewed. Through these methods, he secured the loyalty of the government, allowing the Medici family to establish a de facto principate starting in 1434.12