Obviously I'll state my opinion.

US citizens should have obligated service to their country for at least 2 years. I'm not advocating for only conscription but for other forms of service. In my idea of it a citizen when they turn 18 (or after finishing high school) would be obligated to do one of the following for 2 years:

1. Obviously military would be an option
2. police work
3. Firefighting
4. low level social work
5. rapid emergency response (think hurricane hits Florida, people doing this work would be doing search and rescue, helping with evacuation, transporting necessary materials).
   

On top of that each work would be treated the same as military work, so you'd be under strict supervision, potentially live in barracks, have high standards of discipline, etc etc.