Cal. Const. art. XXI, § 3

(a) The commission has the sole legal standing to defend any action regarding a certified final map, and shall inform the Legislature if it determines that funds or other resources provided for the operation of the commission are not adequate. The Legislature shall provide adequate funding to defend any action regarding a certified map. The commission has sole authority to determine whether the Attorney General or other legal counsel retained by the commission shall assist in the defense of a certified final map.

(b) (1) The California Supreme Court has original and exclusive jurisdiction in all proceedings in which a certified final map is challenged or is claimed not to have taken timely effect.

(2) Any registered voter in this state may file a petition for a writ of mandate or writ of prohibition, within 45 days after the commission has certified a final map to the Secretary of State, to bar the Secretary of State from implementing the plan on the grounds that the filed plan violates this Constitution, the United States Constitution, or any federal or state statute. Any registered voter in this state may also file a petition for a writ of mandate or writ of prohibition to seek relief where a certified final map is subject to a referendum measure that is likely to qualify and stay the timely implementation of the map.

(3) The California Supreme Court shall give priority to ruling on a petition for a writ of mandate or a writ of prohibition filed pursuant to paragraph (2). If the court determines that a final certified map violates this Constitution, the United States Constitution, or any federal or state statute, the court shall fashion the relief that it deems appropriate, including, but not limited to, the relief set forth in subdivision (j) of Section 2.