Missouri Revised Statutes Title IX. Suffrage and Elections § 115.526. Qualifications of candidates may be challenged, by whom, procedure--disqualification, when

1. Any candidate for nomination to an office at a primary election may challenge the declaration of candidacy or qualifications of any other candidate for nomination to the same office to seek or hold such office, or to have his name printed on the ballot, and any candidate for election to an office at a general or special election may challenge the declaration of candidacy or qualifications of any other candidate for election to the same office to seek or hold such office or to have his name printed on the ballot. Except as provided in sections 115.563 to 115.573, challenges shall be made by filing a verified petition with the appropriate court as is provided for in case of a contest of election for such office in sections 115.527 to 115.601. The petition shall set forth the points on which the challenger wishes to challenge the declaration of candidacy or qualifications of the candidate and the facts he will prove in support of such points, and shall pray leave to produce his proof.

2. In the case of challenge to a candidate for nomination in a primary election, the petition shall be filed not later than thirty days after the final date for filing for such election. Except as otherwise provided by law, in the case of challenge to a candidate for election to an office in a general or special election, the petition shall be filed not later than five days after the latest date for certification of a candidate by the officer responsible for issuing such certification. In the case of a disability occurring after said respective deadlines, the petition shall be filed not later than five days after the disability occurs or is discovered. Answers to the petition may be filed at the time and as provided in sections 115.527 to 115.601, specifying the qualifications of the candidate for holding the office for which he is a candidate for election or for nomination.

3. The procedure in such matters shall be the same as that provided in sections 115.527 to 115.601, to the extent that it is applicable and not in conflict with the provisions of this section. For the purposes of this section, as used in sections 115.527 to 115.601 the word “contestant” shall mean the challenger and the word “contestee” shall mean the candidate whose declaration of candidacy or qualifications are challenged. If the court determines that the candidate challenged is not qualified to seek or hold the office for which he is a candidate for nomination or for election or to have his name printed on the ballot, it shall so rule. The right of appeal exists, and may be taken, as provided in sections 115.527 to 115.601.

4. Any candidate finally determined to be not qualified to seek or hold the office for which he is a candidate for nomination or for election shall be disqualified as a candidate for nomination for such office at the primary election or as a candidate for election to such office at the general or special election, as the case may be. Except as otherwise provided by law, whenever a candidate for nomination or election to an office dies, withdraws or is disqualified prior to the election, such candidate's name shall not be printed on the official ballot.