Complex sentence: National gun politics usually focus on the rights, responsibilities and restrictions on the use of guns by nationally sponsored groups; the police, military, etc. They also place rights, restrictions, and responsibilities on their civil populations and groups.
Split into simpler sentences: National gun politics usually focus on the rights, responsibilities and restrictions on the use of guns by nationally sponsored groups; the police, military, etc. decide on the appropriate rights, restrictions, and responsibilities for civilians and civilian groups. They may also place rights, restrictions, and responsibilities on their civil populations and groups.