Mo. Const. art. III, § 3 – Election of representatives — legislative redistricting methods — house independent bipartisan citizens commission, appointment, duties, compensation — court actions, procedure

(a) The house of representatives shall consist of one hundred sixty-three members elected at each general election and redistricted as provided in this section.
(b) The house independent bipartisan citizens commission shall redistrict the house of representatives using the following methods, listed in order of priority:
(1) Districts shall be as nearly equal as practicable in population, and shall be drawn on the basis of one person, one vote. Districts are as nearly equal as practicable in population if no district deviates by more than one percent from the ideal population of the district, as measured by dividing the number of districts into the statewide population data being used, except that a district may deviate by up to three percent if necessary to follow political subdivision lines consistent with subdivision (4) of this subsection;
(2) Districts shall be established in a manner so as to comply with all requirements of the United States Constitution and applicable federal laws, including, but not limited to, the Voting Rights Act of 1965 (as amended). The following principles shall take precedence over any other part of this constitution: no district shall be drawn in a manner which results in a denial or abridgment of the right of any citizen of the United States to vote on account of race or color; and no district shall be drawn such that members of any community of citizens protected by the preceding clause have less opportunity than other members of the electorate to participate in the political process and to elect representatives of their choice;
(3) Subject to the requirements of subdivisions (1) and (2) of this subsection, districts shall be composed of contiguous territory as compact as may be. Areas which meet only at the points of adjoining corners are not contiguous. In general, compact districts are those which are square, rectangular, or hexagonal in shape to the extent permitted by natural or political boundaries;
(4) To the extent consistent with subdivisions (1) to (3) of this subsection, communities shall be preserved. Districts shall satisfy this requirement if district lines follow political subdivision lines to the extent possible, using the following criteria, in order of priority. First, each county shall wholly contain as many districts as its population allows. Second, if a county wholly contains one or more districts, the remaining population shall be wholly joined in a single district made up of population from outside the county. If a county does not wholly contain a district, then no more than two segments of a county shall be combined with an adjoining county. Third, split counties and county segments, defined as any part of the county that is in a district not wholly within that county, shall each be as few as possible. Fourth, as few municipal lines shall be crossed as possible;
(5) Districts shall be drawn in a manner that achieves both partisan fairness and, secondarily, competitiveness, but the standards established by subdivisions (1) to (4) of this subsection shall take precedence over partisan fairness and competitiveness. "Partisan fairness" means that parties shall be able to translate their popular support into legislative representation with approximately equal efficiency. "Competitiveness" means that parties' legislative representation shall be substantially and similarly responsive to shifts in the electorate's preferences.
To this end, the average electoral performance of the two political parties receiving the most votes in the three preceding general elections for governor, for United States Senate, and for President of the United States shall be calculated. This index shall be defined as the total votes received by each party in the three preceding general elections for governor, for United States Senate, and for President of the United States, divided by the total votes cast for both parties in these elections. Using this index, the total number of wasted votes for each party, summing across all of the districts in the plan shall be calculated. "Wasted votes" are votes cast for a losing candidate or for a winning candidate in excess of the threshold needed for victory. In any redistricting plan and map of the proposed districts, the difference between the two parties' total wasted votes, divided by the total votes cast for the two parties, shall not exceed fifteen percent.
To promote competitiveness, the electoral performance index shall be used to simulate elections in which the hypothetical statewide vote shifts by one percent, two percent, three percent, four percent, and five percent in favor of each party. The vote in each individual district shall be assumed to shift by the same amount as the statewide vote. In each of these simulated elections, the difference between the two parties' total wasted votes, divided by the total votes cast for the two parties, shall not exceed fifteen percent.
(c) Within sixty days after the population of this state is reported to the President for each decennial census of the United States or, in the event that a redistricting plan has been invalidated by a court of competent jurisdiction, within sixty days that such a ruling has been made, the state committee and the congressional district committees of each of the two political parties casting the highest vote for governor at the last preceding general election shall meet and the members of each committee shall nominate, by a majority vote of the elected members of the committee present, provided that a majority of the elected members is present, members of their party, residents in that district, in the case of a congressional district committee, as nominees for the house independent bipartisan citizens commission. No party shall select more than one nominee from any one state legislative district. The congressional district committees shall each submit to the governor their list of two elected nominees. The state committees shall each submit to the governor their list of five elected nominees. Within thirty days thereafter, the governor shall appoint a house independent bipartisan citizens commission consisting of one nominee from each list submitted by each congressional district committee and two nominees from each list submitted by each state committee to redistrict the state into one hundred and sixty-three representative districts and to establish the numbers and boundaries of said districts. No person shall be appointed to both the house independent bipartisan citizens commission and the senate independent bipartisan citizens commission during the same redistricting cycle.
If any committee fails to submit a list within such time, the governor shall appoint a member of his or her own choice from the political party of the committee failing to submit a list, provided that in the case of a congressional district committee failing to submit a list, the person appointed to the commission by the governor shall reside in the congressional district of such committee.
Members of the commission shall be disqualified from holding office as members of the general assembly for four years following the date of the filing by the commission of its final redistricting plan.
For the purposes of this Article, the term congressional district committee or congressional district refers to the congressional district committee or the congressional district from which a congressman was last elected, or, in the event members of congress from this state have been elected at large, the term congressional district committee refers to those persons who last served as the congressional district committee for those districts from which congressmen were last elected, and the term congressional district refers to those districts from which congressmen were last elected. Any action pursuant to this section by the congressional district committee shall take place only at duly called meetings, shall be recorded in their official minutes and only members present in person shall be permitted to vote.
(d) The commissioners so selected shall, on the fifteenth day, excluding Sundays and state holidays, after all members have been appointed, meet in the capitol building and proceed to organize by electing from their number a chairman, vice chairman and secretary. The commission shall adopt an agenda establishing at least three hearing dates on which hearings open to the public shall be held to hear objections or testimony from interested persons. A copy of the agenda shall be filed with the clerk of the house of representatives within twenty-four hours after its adoption. Executive meetings may be scheduled and held as often as the commission deems advisable.
(e) Not later than five months after the appointment of the commission, the commission shall file with the secretary of state a tentative redistricting plan and map of the proposed districts and during the ensuing fifteen days shall hold such public hearings as may be necessary to hear objections or testimony of interested persons. The commission shall make public the tentative redistricting plan and map of the proposed districts, as well as all demographic and partisan data used in the creation of the plan and map.
(f) Not later than six months after the appointment of the commission, the commission shall file with the secretary of state a final statement of the numbers and the boundaries of the districts together with a map of the districts, and no statement shall be valid unless approved by at least seven-tenths of the members.
(g) After the final statement is filed, members of the house of representatives shall be elected according to such districts until a new redistricting plan is made as provided in this section, except that if the final statement is not filed within six months of the time fixed for the appointment of the commission, the commission shall stand discharged and the house of representatives shall be redistricted using the same methods and criteria as described in subsection (b) of this section by a commission of six members appointed from among the judges of the appellate courts of the state of Missouri by the state supreme court, a majority of whom shall sign and file its redistricting plan and map with the secretary of state within ninety days of the date of the discharge of the house independent bipartisan citizens commission. The judicial commission shall make public the tentative redistricting plan and map of the proposed districts, as well as all demographic and partisan data used in the creation of the plan and map. Thereafter, members of the house of representatives shall be elected according to such districts until a redistricting plan is made as provided in this section.
(h) Each member of the commission shall receive as compensation fifteen dollars a day for each day the commission is in session but not more than one thousand dollars, and, in addition, shall be reimbursed for his or her actual and necessary expenses incurred while serving as a member of the commission.
(i) No redistricting plan shall be subject to the referendum.
(j) Any action expressly or implicitly alleging that a redistricting plan violates this Constitution, federal law, or the United States Constitution shall be filed in the circuit court of Cole County and shall name the body that approved the challenged redistricting plan as a defendant. Only an eligible Missouri voter who sustains an individual injury by virtue of residing in a district that exhibits the alleged violation, and whose injury is remedied by a differently drawn district, shall have standing. If the court renders a judgment in which it finds that a completed redistricting plan exhibits the alleged violation, its judgment shall adjust only those districts, and only those parts of district boundaries, necessary to bring the map into compliance. The supreme court shall have exclusive appellate jurisdiction upon the filing of a notice of appeal within ten days after the judgment has become final.