Mo. Rev. Stat. § 563.041 (2026)

  563.041.  Use of physical force in defense of property. — 1.  A person may, subject to the limitations of subsection 2, use physical force upon another person when and to the extent that he or she reasonably believes it necessary to prevent what he or she reasonably believes to be the commission or attempted commission by such person of stealing, property damage or tampering in any degree.

  2.  A person may use deadly force under circumstances described in subsection 1 only when such use of deadly force is authorized under other sections of this chapter.

  3.  The justification afforded by this section extends to the use of physical restraint as protective force provided that the actor takes all reasonable measures to terminate the restraint as soon as it is reasonable to do so.

  4.  An armed nuclear security guard may use the following levels of physical force against another person at a nuclear power plant or within a structure or fenced yard of a nuclear power plant if the armed nuclear security guard reasonably believes that such force is necessary:

  (1)  An armed nuclear security guard may use physical force, as he or she reasonably believes is immediately necessary, up to and including deadly physical force to:

  (a)  Prevent an action that would constitute murder in the first or second degree under section 565.020 or 565.021;

  (b)  Prevent an action that would constitute voluntary manslaughter under section 565.023;

  (c)  Prevent an action that would constitute assault in the first or second degree under section 565.050 or 565.052; or

  (d)  Defend himself, herself, or a third person from the use or imminent use of deadly physical force;

  (2)  An armed nuclear security guard may use physical force, as he or she reasonably believes is immediately necessary, up to but not including deadly physical force to prevent an action that would constitute:

  (a)  Assault in the third or fourth degree under section 565.054 or 565.056;

  (b)  Kidnapping in the first, second, or third degree under section 565.110, 565.120, or 565.130;

  (c)  Burglary in the first or second degree under section 569.160 or 569.170;

  (d)  Arson in the first, second, or third degree under section 569.040, 569.050, or 569.053;

  (e)  Property damage in the first degree under section 569.100;

  (f)  Robbery in the first or second degree under section 570.023 or 570.025;

  (g)  Armed criminal action under section 571.015; or

  (h)  Trespass in the first degree under section 569.140;

  (3)  An armed nuclear security guard is justified in threatening to use physical force or deadly physical force if and to the extent a reasonable armed nuclear security guard believes it necessary to protect himself, herself, or others against another person's potential use of physical force or deadly physical force.

  5.  Notwithstanding any provisions of section 563.016 to the contrary, an armed nuclear security guard, employer of an armed nuclear security guard, or owner of a nuclear power plant shall not be subject to civil liability for conduct of an armed nuclear security guard that is permitted by this section.

  6.  The defendant shall have the burden of injecting the issue of justification under this section.