Final answer:
First Ladies of the United States have promoted their own causes that connect with changing social issues like education and drug use.
Step-by-step explanation:
First Ladies of the United States have had an effect on national policy by promoting their own causes that connect with changing social issues like education and drug use. For example, Lady Bird Johnson advocated for highway beautification, Nancy Reagan launched an anti-drug crusade, and Barbara Bush focused on literacy programs. Michelle Obama also made an impact by advocating for healthy eating and working with Walmart to lower prices on healthier food options.