Shaw v. Reno is a landmark Supreme Court case from 1993 that addressed the issue of racial gerrymandering in North Carolina's congressional redistricting plan. The Court ruled that redistricting plans that are excessively based on race violate the Equal Protection Clause of the Fourteenth Amendment, emphasizing that while race can be a factor in drawing district lines, it cannot be the predominant factor. This case set important precedents for how states must approach redistricting, ensuring that they do not engage in practices that unfairly dilute or enhance the voting power of racial groups.