In Electoral College Reform: Contemporary Issues for Congress, Thomas H. Neale states that the United States takes an unusual approach to Presidential and Vice Presidential elections on Page 1 of the Introduction:
The United States is unusual among contemporary presidential republics by providing for the indirect election of its President and Vice President
Furthermore, in his footnote, he states that other Presidential Republics have universally adopted a direct election of the President, stating:
Direct election of the President is currently universal in presidential republics that provide for a strong chief executive, combining the roles of head of state and head of government, e.g., Mexico and Brazil.
That fact that this was an anomaly among similar kinds of republics prompted me to ask this question..
Why have other Presidential Republics universally instituted a direct election of its chief executive?