What act required that all U.S. citizens be treated equally under the law?

The Civil Rights Act of 1964 is recognized as a landmark piece of legislation that required all U.S. citizens to be treated equally under the law. Its primary goal was to eliminate discrimination based on race, color, religion, sex, or national origin. This act aimed to ensure equal access to public accommodations, schools, and employment, marking a significant step forward in the civil rights movement.

The act established legal protections that prohibited discriminatory practices and empowered the federal government to enforce these rights, thus fostering a more equitable society. By addressing various areas of public life, it laid a foundation for future legal measures related to civil rights and social justice. The act's comprehensive nature is why it is often cited as a pivotal moment in U.S. history concerning equality under the law.