Complex sentence: His father was a lawyer for the Fair Districts movement which ended partisan gerrymandering in Florida by proving that the Florida constitution was violated by the state legislature when it redrew the congressional and State Senate district lines.
Split into simpler sentences: His father was a lawyer for the fair districts movement that was known for ending partisan gerrymandering in Florida. The movement proved the Florida constitution was violated by the state legislature when it redrew the congressional and State Senate district lines.