Missouri Redistricting Process


Congressional maps are enacted by the State General Assembly. The Governor can veto the plans.

The General Assembly can override a veto with a two-thirds vote. Republicans currently have veto-proof majorities in both chambers.


Districts for the Missouri House of Representatives and Senate are drawn by the House Independent Bipartisan Citizens Commission and the Senate Independent Bipartisan Citizens Commission, respectively. Both Commissions’ members are nominated by the state’s political party committees and appointed by the governor.

Within sixty days of the state’s census population being reported, both the state and congressional district committees of each of the two political parties casting the highest vote for governor at the last preceding general election submit nomination lists to the governor. Each state committee nominates five, and each congressional district committee nominates two of their elected members for each Commission. Neither party can select more than one nominee from any one state legislative district, no person may be appointed to both the House and Senate Commissions for the same redistricting cycle, and the congressional district committees’ nominees must be residents of that committee’s district. Within thirty days of receiving the nomination lists, the governor appoints one Commissioner from each of the congressional district committees’ lists and two Commissioners from each of the state committees’ lists to each Commission. If either party’s committee fails to submit a list of nominees by the deadline, the governor appoints the needed number of commissioners from the pool of elected members of the political party that failed to submit a list, subject to the same eligibility requirements.

Within five months of the commissioners’ appointment, the Commission must file their tentative plan and map of proposed districts with the Secretary of State and publicly release them, along with any demographic and partisan data used in their creation. Over the proceeding fifteen days, the Commission must hold public hearings. No later than six months after the commissioners’ appointment, the Commission must submit a finalized statement of their plan to the Secretary of State, which must have been approved by at least seven-tenths of the commissioners.

If a commission fails to file their finalized plan by the deadline, the commission is discharged, and the plan will be drawn by a commission of Missouri appellate court judges who are selected by the Missouri supreme court. The judicial commission’s plan must be submitted to the Secretary of State and released to the public, including any underlying data used in its creation, within ninety days of the relevant commission’s dissolution. Challenged to maps are filed in the Cole County circuit court by any registered Missouri voter residing in the district affected by the alleged violation, and the Missouri Supreme Court has exclusive appellate jurisdiction.

Source: Mo. Const. art. III, §§ 3, 7.

Previous Redistricting Cycles


  • Congressional
    • Original PlanHB 193
      • Passed = April 27, 2011 (R-controlled)
      • Vetoed = May 2, 2011 (D-controlled)
      • Veto Overridden = May 4, 2011 (R-controlled)
    • Litigation History
      • Pearson v. Koster, 367 S.W.3d 36 (Mo. 2012): Two groups of plaintiffs filed a lawsuit challenging the General Assembly’s enacted congressional plan on the grounds it failed to sufficiently comply with the state constitution’s compactness requirement. On May 25, 2012, the Missouri Supreme Court affirmed the trial court’s judgment that the plan sufficiently complied with the constitutional compactness requirement.
  • Legislative
    • Appellate Apportionment Commission’s Original Plans (House and Senate Reapportionment Commissions failed to adopt plans, so backup commission of appellate court judges adopted plans)
      • Adopted = November 30, 2011
    • Reapportionment Commission’s Revised Senate Plan
      • Adopted = December 9, 2011
    • 2nd Commission’s Revised Senate Plan
      • Adopted = March 12, 2012
    • Litigation History
      • State ex rel. Teichman v. Carnahan, 357 S.W.3d 601 (Mo. 2012): After the Senate Reapportionment Commission filed its revised Senate Plan on December 9, 2011, a registered Missouri voter filed a lawsuit challenging the constitutionality of the Appellate Commission’s original Senate plan and the Reapportionment Commission’s revised Senate plan on the grounds that the commission lacked authority to adopt the December 9, 2011 revised plan and that the original Senate plan violated the state Constitution by excessively dividing counties. On January 17, 2012, the Missouri Supreme Court ruled that the commission lacked authority to adopt the revised Senate plan, that the original Senate plan violated the state constitution, and ordered that a new plan be drawn.
      • Johnson v. State, 366 S.W.3d 11 (Mo. 2012): A group of Missouri voters filed a lawsuit challenging the General Assembly’s enacted House plan as violating the state constitution’s requirements for population, contiguity, and compactness, in addition to asserting procedural violations in its enactment. On May 25, 2012, the Missouri Supreme Court affirmed the trial court’s judgment in favor of the defendants, finding that the plaintiffs failed to prove the House plan violated the state constitution and that the reapportionment commission did not violate state law when enacting it.


  • Congressional
    • Original PlanHB 1000
      • Passed = May 29, 2001 (Split-control)
      • Signed = June 1, 2001
    • Litigation History
      • None
  • Legislative
    • Appellate Apportionment Commission’s Plans (House and Senate Reapportionment Commissions failed to pass plans)
      • Passed = November 30, 2001
    • Litigation History
      • None

Governor Bill Signing

If a bill is presented to the governor during session, the governor has 15 days to sign or veto it; otherwise, it becomes law without signature. If the bill is delivered to the governor during the last 15 days of the session, the governor must sign or veto it within 45 days of session adjournment; otherwise, it becomes law. Sundays are not excluded in these calculations. Line-item vetoes are permitted.

Ballot Measure Process

Kinds of Ballot Measures
Direct initiatives and all referendums are permitted to amend statutes. Direct initiatives are permitted to amend the state constitution. Legislatively initiated ballot measures may amend both statutes and the constitution.

Single-Subject Rule
There is a single-subject rule.

Initiative Subject Restrictions
Ballot measures must be constitutionally permissible.

Signature Requirements
The signature requirement for constitutional amendments is 8% of all legal voters in each of two-thirds of the congressional districts of the state, 5% for statutory amendments, and 5% for veto referendums. The number of legal voters is based upon the total vote for governor at the last general election preceding the petition filing. Therefore, at least 171,591 signatures are required for constitutional amendments, and 107,245 signatures are required for statutory amendments as well as referendums, but this number depends on the districts from which signatures are gathered. District information can be found here.

Submission Deadlines
Initiative petitions must be submitted six months prior to the election in which the petition is to appear on the ballot (May 6, 2022). Referendum petitions must be submitted to the Secretary of State no more than 90 days after the adjournment of the session which passed the bill in question.

Circulation Period
The circulation period for initiative petitions is 18 months.

Ballot Title and Summary
The ballot title and summary are written by the Secretary of State and approved by the Attorney General. Expedited reviews for titles and summaries are permitted.

Other Requirements
A fiscal impact statement is required. Circulators must be at least 18 years of age and registered with the Secretary of State. There are no supermajority requirements. The General Assembly can amend or repeal a voter-approved statute, but must follow constitutional guidelines to amend or repeal amendments. Referendums cannot target laws making appropriations for the current expenses of the state government or emergency legislation. Initiatives are permitted on general election ballots, but not on primary or special election ballots or odd-year ballots.

Source: Mo. Const. art. III, §§ 50-53. Mo. Rev. Stat. § 116 (2019). Missouri Secretary of State Website

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