By the late 20th century, the majority of the world's countries had a prime minister or equivalent minister, holding office under either a constitutional monarchy or a ceremonial <answer>president</answer>. The main exceptions to this system have been the United States and the <answer>president</answer>ial republics in Latin America modelled on the U.S. system, in which the <answer>president</answer> directly exercises executive authority.
In the U.S. and governments modeled on it, who holds executive power?
president