Final answer:
In the 1930s, the NAACP brought test cases to court and challenged segregationist practices to fight for equality in the United States. Led by Thurgood Marshall, they successfully argued against substandard facilities for blacks and won key victories in the Supreme Court.
Step-by-step explanation:
In the 1930s, the NAACP (National Association for the Advancement of Colored People) continued to work towards achieving equality for minority groups in the United States. One of their main strategies during this time was bringing test cases to court that challenged segregationist practices. Led by Thurgood Marshall, the NAACP urged the courts to nullify programs that provided substandard facilities for blacks, arguing that they violated the principle of "separate but equal." Their efforts resulted in key victories, such as the 1937 Supreme Court ruling that Missouri was denying equal protection by providing a state law school for whites without extending the same opportunity to blacks. These triumphs made Southern states take the concept of "separate but equal" more seriously, sometimes leading to the allocation of funds for black colleges, which became centers for political action.