Final answer:
Mexico, Argentina, and Brazil struggled with maintaining democracy throughout the latter half of the 20th century.
Step-by-step explanation:
The countries that struggled with maintaining democracy throughout the latter half of the 20th century were Mexico, Argentina, and Brazil. In Argentina, for example, there were several military coups and periods of military rule that led to political instability and economic turmoil. Brazil also faced similar challenges with military interventions and political unrest. Mexico experienced corruption, election fraud, and power struggles that hindered the development and stability of democracy.