Conscription is a bad idea, for a lot of reasons. However, there are presently grave difficulties in maintaining a middle-size volunteer army.
In true peacetime, only a handful of recruits are needed: no problem. In full-out wartime, everyone is expected to volunteer, and nearly all do: no problem.
In the middle range, where we are now, it gets very awkward: we only want _some_ people to volunteer. And those who do make a sacrifice that we don’t condemn others for not making. Material rewards aren’t the answer: we don’t want mercenaries, and upper class youth can’t be bought for cash.
The Work Corps idea is useful: there are a lot of things that need doing that are unpleasant and psychologically stressful, including but not only war, and those burdens should be shared generally.
Rather than make national service compulsory, I would make it _expected_. Everyone gets a notice to show up. One can blow off the notice – but then one gets the equivalent of a “white feather”. Military service is an option. So is service in other areas – border protection, disaster relief, care for the mentally disabled, public works, the Peace Corps, etc.
Military service would have the most prestige. A lot more people would consider military service if they were going to spend years doing something similar anyway. I would also make it possible for people to do service at various ages – so that people in their late 20s up to their 50s could serve.
