The treatment of Manning and eventual treatment of Assange will be our generation's Vietnam - an active demonstration of our government's willingness to lie to and abuse us, a touchstone for all who are seeking a reason not to cooperate.
It would certainly be nice if that was the case. However, it's much more likely the average American doesn't know (or care) about Manning, other than the occasional footnote on the 10 o'clock news, and in a year or two he will be forgotten.