Just finished doing taxes, so a few random thoughts:
There's a survey out showing that Americans have a sense of social cohesion from doing their taxes.
There's also a theory about the benefits of national service, including a thread today on Twitter.(I'm not sufficiently up on it enough to include a url but this tweet from Lyman Stone may help:"@tylercowen @dylanmatt @hyperplanes 1. it's not inherited, 2. you get paid a market wage, 3. it's temporary, 4. you can't be sold, 5. you can't be bought, 6. working conditions")
As someone who was drafted and didn't like it, I do recognize some benefits from it: in a sense it's creative destruction, disrupting established patterns and possibly promoting social mobility. It also might promote social cohesion, giving people a shared experience.
Unfortunately for its promoters a good bit of the possible benefits is bound up in the military aspect: the social cohesion bit derives from the pain the military inflicts, the basic training and the regimentation. It's like a fraternity, conventional wisdom probably says that the greater the hazing, the greater fraternal feeling.