Final answer:
The NAACP's strategy in the 1930s focused on legal challenges to segregation, compelling Southern states to adhere to the 'separate but equal' doctrine and eventually leading to the provision of facilities and institutions for African Americans.
Step-by-step explanation:
In the 1930s, the NAACP employed a legal strategy aimed at challenging segregationist practices. Thurgood Marshall, a key figure in this movement, led the charge by advocating the courts to consider the substandard facilities for African Americans a violation of the "separate but equal" doctrine. This approach garnered a significant victory in 1937 when the Supreme Court ruled that Missouri's provision of a state law school for whites and not for blacks denied equal protection, thereby compelling Southern states to fund institutions for black Americans.
Moreover, by the mid-20th century, the NAACP legal strategy had secured a number of critical successes, including the challenge of segregation in education. The organization's tactic led to a 1938 Supreme Court decision that forced states to either integrate higher education or create equivalent institutions for African Americans. While this allowed for more educational opportunities and established black colleges as political action centers, it did not dismantle the segregated system entirely.
The civil rights movement in the following decades further expanded on these legal foundations, leading to groundbreaking rulings like Brown v. Board of Education in 1954 that signaled the eventual end of legalized racial segregation in education.