For countries with mandatory military service, Church members must generally complete their military service before they can serve a mission. Some countries may allow the mandatory military service to be deferred until after the missionary service. Priesthood leaders should become familiar with their country’s requirements so they can advise members appropriately.
The United States has an all-volunteer military and does not have a draft, so military service is not mandatory. However, men ages 18 through 25 are required by law to register with the Selective Service System at sss.gov within 30 days of their 18th birthday. Also, there are the following restrictions on when a Church member who has joined the military can serve a mission:
Active duty. Church members who serve on active duty must complete their active-duty commitment before they can serve a mission.
Reserve or National Guard. Church members who join the Reserve or National Guard may serve their mission once they complete basic and advanced training unless their military unit is scheduled to deploy in support of military operations. If the unit is scheduled to deploy, the member will not be able to serve a mission until he or she returns from the deployment.
Normally, military members incur a six-year active Reserve or National Guard commitment, followed by two years of inactive Reserve or National Guard time. There is a provision in the regulations that allows for missionary service during the inactive portion of the commitment. The two years of inactive Reserve or National Guard time may be moved forward to allow Church members to serve missions once they complete their basic and advanced training, although such authorization is contingent upon chain of command approval and real-world circumstances. When the members return from their missions, they report back to their military unit and complete the remaining active Reserve or National Guard commitment. Unless the members are activated for extended military operations, the active Reserve or National Guard obligation involves one weekend a month and two weeks of annual training.
Military service academies and other officer commissioning programs. Church members who are selected to attend one of the service academies may resign their appointment after their first or second year to serve a mission. To be readmitted, they are required to reapply and receive another nomination letter from a congressman or senator. As long as they have maintained good academic and military standards, there are generally no problems with their being readmitted. With other officer commissioning programs, there are some restrictions on when Church members can leave to serve a mission, but if members follow these restrictions, they can leave to serve a mission and return without any problems.
For further information and additional resources, priesthood leaders should contact the Military Relations and Chaplain Services Division at 801-240-2286 or PST-Military@ChurchofJesusChrist.org.