The Homeland Defense System is an Everetti Department of Defense civil defense program. Established in 2005, the HDS consists of a national federal registry of gun owners, a requirement of purchasing Class 3 firearms, that requires the registrant to join a civil defense emergency reserve force. The HDS can be activated by the Secretary of Defense and the President of the Union of Everett in response to an invasion of the Everetti mainland, natural disaster or during times of civil unrest.