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What Is a Presidential Republic? - Constitution of The United States
World Factbook Glyph
Presidential system - Wikipedia
Is America a democracy or a republic? Yes, it is : NPR
List of countries by system of government - Wikipedia
10.4 Advantages, Disadvantages, and Challenges of Presidential …
presidency of the United States of America - Encyclopedia Britannica
President | Definition, Responsibilities, & History | Britannica
list of presidents of the United States - Encyclopedia Britannica
How the president is elected | USAGov