Or another way:
What are the odds that we (any 'we' coalition) could Get Through Congress any form of draft via which *their* offspring have no [repeat: No] special access to deferments or other opt-outs?
See, I think that's a more direct solution to zealot-Warz than your dream, of the perpetually uninvolved majority of non-voters performing some actual grass-roots Action. And with a hell of a lot less delay ... .... ... awaiting some next election (were such a Bill possible, such as we are today).