If scholarly research finds that these things can help to reduce crime, then the government would need to find ways to promote them so that the likelihood of crime can be reduced. Of course, marriage, jobs, and military service are different things and different policies would be needed to promote them. It is also not clear that actions that the government could take would be effective in reducing crime.
For example, if the government wanted to use military service to reduce crime, it would likely need to lower the standards for military recruitment so as to allow more people who are at risk of becoming criminals to join the military. This would be problematic because the military is not likely to want to start taking people who did not finish high school or who seem to have too much in the way of a criminal record. Thus, it becomes difficult to use the military as a way to reduce crime.
Similarly, it is difficult to get a lot of people into jobs. Many of the people who are most likely to commit crimes lack the qualifications needed for most jobs. The government could create massive make-work programs to give these people jobs, but it is not clear these would really be a good idea and it is even less clear that they could ever be created in today’s political and economic climate.
Thus, it is clear in theory that the government would need to promote military service, work, and marriage. What is much less clear is that the government could actually do so in any effective way.