In Plessy v Ferguson the Supreme Court ruled that segregation based on race is legal so long as the standard of “separate but equal” is met.
In Dred Scott v Sanford, the court ruled that blacks were not and could not be citizens and that “The black man has no civil rights that the White man is bound to respect”.
In Roe v Wade the court ruled that laws making abortion illegal during thre first trimester of pregnancy are unconstitutional.
The first two of these have been overturned, and hopefully the third will be. A SCOTUS decision carries weight, but is neither infallible nor unchangeable.