This article explores how military service helps people overcome barriers to volunteering, because they become socialised to accept civic responsibilities and gain social resources and skills, which can be harnessed subsequently through volunteering. This suggests voluntary civic engagement somehow replicates elements familiar to those who serve in the military. However, they are careful not to conflate the two absolutely, pointing out that comparing the two may diminish the sacrifice and status of military service.
Research shows that military service is linked with political engagement, such as voting. The connection is strongest for minorities. The authors explore the relationship between military service and volunteering. They conclude that military service helps overcome barriers to volunteering by socializing people with civic responsibility norms, by providing social resources and skills that compensate for the lack of personal resources, and by making veterans aware of opportunities to volunteer as well as asking them to do so. Military service is positively related to volunteering among blacks and Hispanics. Married veterans are more likely to volunteer than non-veterans. Veterans who served during wartime are more likely to volunteer than those who served in peacetime.
Nesbit, R. and Rheingold, D. A., 2011. Soldiers to Citizens: The Link between Military Service and Volunteering. Public Administration Review, 71(1), 67-76.