MO SB1246

Creates a presumption of reasonableness that a defendant believed force was necessary for self-defense, replacing the current standard where defendants must inject the issue of justification and the state proves unreasonableness beyond a reasonable doubt

Establishes immunity from both criminal prosecution and civil lawsuits for persons who use or threaten force in lawful self-defense, with "criminal prosecution" defined to include arrest, detention, and charging

Prohibits law enforcement from arresting a person for using or threatening force unless the agency determines probable cause exists that the force was unlawful

Shifts the burden of proof at pretrial immunity hearings to the party seeking to overcome self-defense immunity, requiring clear and convincing evidence to defeat the claim

Repeals Section 563.016, which previously preserved civil remedies against persons whose conduct was justified under self-defense law