Final answer:
Deportations decreased during WWII mainly because Mexican workers were needed for the war effort.
Step-by-step explanation:
Deportations decreased during WWII mainly because Mexican workers were needed for the war effort. The United States faced a shortage of agricultural laborers and initiated the Bracero Program, which allowed Mexican braceros or hired hands to harvest crops. This program provided a steady supply of labor and offered protection to Mexican guest workers, reducing the need for deportations.