four National Defense Service Medals in each of four eras): Korean War Vietnam War Gulf War War on Terrorism Unit awards Service stars are authorized for certain unit awards (The service ribbon itself indicates the first award, with a bronze service star being added to indicate the second and subsequent awards. If ever applicable, a silver service star is worn instead of five bronze stars.) such as the: Presidential Unit Citation (Navy and Marine Corps) Navy Unit Commendation (Navy and Marine Corps) Campaign stars Campaign stars are authorized for these United States campaign medals (bronze and silver campaign stars are worn to denote participation in a designated campaign or campaign phase or period): World War I Victory Medal American Defense Service Medal American Campaign Medal Asiatic–Pacific Campaign Medal European–African–Middle Eastern Campaign Medal Korean Service Medal Vietnam Service Medal Southwest Asia Service Medal* Kosovo Campaign Medal Afghanistan Campaign Medal Iraq Campaign Medal Inherent Resolve Campaign Medal For each designated campaign participated in, one star is worn on the ribbon. For example, when a member is authorized to wear the Iraq Campaign Medal, the potential addition of bronze and silver service stars for the seven designated Iraq Campaign phases would be: For many of these awards, service stars are earned by participation in campaign phases and all eligible periods for the award fall within those defined phases. In these cases, the campaign medal cannot be earned alone, and is always to be worn with at least one campaign star. Battle stars Since February 26, 2004, the Global War on Terrorism Expeditionary Medal and the Global War on Terrorism Service Medal (GWOT-SM) are authorized to be awarded with bronze and silver battle stars for personnel who were engaged in specific battles in combat under circumstances involving grave danger of death or serious bodily injury from enemy action. However, though authorized for wear, no battle stars have been approved for wear. Only a combatant commander can initiate a request for a battle star, and the Chairman of the Joint Chiefs of Staff is the approving authority, which since January 2016 has been eliminated by the Department of Defense for the GWOT-SM. Only one award of the Global War on Terrorism Expeditionary Medal and one award of the Global War on Terrorism Service Medal may be authorized for any individual. No service stars were authorized for the Global War on Terrorism Expeditionary or Service Medal