The main way in which the separation of powers guards against tyranny is by making it impossible for any single branch to become too powerful, since each branch "checks and balances" the others out when it comes to making and enforcing legislation.
Margaret Brown, known by her friends as Maggie, but after her death as The Unsinkable Molly Brown
Judicial, legislative, and executive
Answer: Brown vs. Board of Education and the Civil Rights Act of 1964
Explanation: The Brown vs. Board of Education and the Civil Rights Act of 1964 supported and created segregation in the United States.