Edgewood ISD v. Kirby was a landmark case in 1989 where the Texas Supreme Court ruled that the state's public school finance system was unconstitutional due to its reliance on local property taxes, which led to significant disparities in funding among school districts. This case highlighted the issues of equity and fairness in education funding and underscored the importance of the state's obligation to provide adequate resources for all students, regardless of their district's wealth.