Mo. Const. art. III, § 8

No one shall be elected to serve more than eight years total in any one house of the General Assembly nor more than sixteen years total in both houses of the General Assembly. In applying this section, service in the General Assembly resulting from an election prior to December 3, 1992, or service of less than one year, in the case of a member of the house of representatives, or two years, in the case of a member of the senate, by a person elected after the effective date of this section to complete the term of another person, shall not be counted. [Effective - 05 Dec 2002 , see footnote]