I did say "mandatory."

More than a few people have called for scrapping the present Homeland Security bureacracy and returning to the old Civil Defense system, which perished due to a violent allergy to the idea that nuclear war was in any way survivable. Unfortunately, the "natural disaster preparedness" baby got thrown out with that bathwater. I did get a good set of surplus rad detectors out of it, though.

Your idea of a new civil service is worth thinking about, although I think this is where things like the National Service Act and Americorps were trying to go.

While I don't think connecting voluntary national service to the franchise, a la "Starship Troopers" is ever going to sell, I could easily see the government offering other benefits to people willing to put in a couple of years on something. Scholarships? Tax breaks? As far as I know, current national service programs don't offer much of anything like this.