Complex sentence: In June 2006 Louisiana Governor Kathleen Blanco signed Senate Bill No.18 (later Act No.560) into law, which took effect in 2008 and returned Congressional races to the closed primary system.
Split into simpler sentences: In June 2006 Louisiana Governor Kathleen Blanco signed Senate Bill No.18 (later Act No.560) into law, which took effect in 2008. It returned Congressional races to the closed primary system.