Final answer:
The most important legal victory for civil rights in the 1950s was the landmark Supreme Court decision in Brown v. Board of Education, which overturned the previous decision in Plessy v. Ferguson and declared segregation in public schools unconstitutional.
Step-by-step explanation:
The most important legal victory for civil rights in the 1950s was the landmark Supreme Court decision in Brown v. Board of Education. This case overturned the previous decision in Plessy v. Ferguson, which had upheld segregation in public schools.
The Supreme Court unanimously ruled in Brown v. Board of Education that mandating or permitting public schools to be segregated by race was unconstitutional. The decision stated that a separate but equal education was a logical impossibility and that segregation in public schools was therefore a violation of the Fourteenth Amendment.
It established that separate educational facilities are inherently unequal, and it laid the groundwork for future civil rights advancements.