The worse the economy is, the more likely people are to join the military. Right now, the unemployment rate in the United States is over ten percent, which is high.
Also, another reason that people would join the military is lack of options. I remember one experience that I had on the "subway" in Buffalo. A woman told me that she had just taken her son to the marine recruiter so that he could enlist. "Oh," I said, dubiously, expressing the idea that, during wartime, taking one's son to the marine recruiter may not be a very good idea. I did not say anything to the woman about the idea that she might end up without a son. The woman responded, "It's better for him than being on the street."
Drugs. Gangs. Drive by shootings.
The kid was already living in a war zone.