Mo. Rev. Stat. § 9.050: May 1, Law Day.

In order to rededicate Missourians to the principles of the democratic form of government; to emphasize that ours is a government of law and not of men; and to further our philosophy that, "The Welfare of the People shall be the Supreme Law", May first of each year shall be designated as "Law Day U.S.A." It is not the purpose of this section to declare another legal holiday, but a day to solemnly declare allegiance to the principles of democracy, and respect for law.