Why do the United States and many Latin American countries not have prime ministers?

The United States and many Latin American countries do not have prime ministers because they have adopted presidential systems of government.21

In these systems, the executive branch is led by a president who serves as both the head of government and the head of state. This structure is defined by a strict separation of powers between the executive and the legislature, meaning the president is elected independently and does not depend on legislative support to remain in office. In contrast, parliamentary systems—which are common in Europe and elsewhere—feature a prime minister who is typically the leader of the largest party in the legislature and must maintain the confidence of that body to govern.2341

The U.S. presidential model, which influenced many Latin American nations, was designed to create an energetic national executive while utilizing checks and balances to prevent the concentration of power. Consequently, while prime ministers in parliamentary systems can be removed through a vote of confidence, presidents in these systems can generally only be removed through formal impeachment proceedings.5312