D&C 134

As The Church discusses its position on governments, they also state -

"We believe that men should appeal to the civil law for redress of all wrongs and grievances, where personal abuse is inflicted or the right of property or character infringed, where such laws exist as will protect the same; but we believe that all men are justified in defending themselves, their friends, and property, and the government, from the unlawful assaults and encroachments of all persons in times of exigency, where immediate appeal cannot be made to the laws, and relief afforded."  (Doctrine and Covenants | Section 134:11)

Obviously, in order to do so, one must have the right to bears arms.