I have worked with people conscripted into their respective nation's military. Let me tell you, the quality of soldier you get is very poor when that soldier has been forced into service and is doing nothing but waiting for that last day to come. Part of the strength of our military comes from the fact that EVERYONE chose to be there. Even the worst of our soldiers were still above the performance level of the conscripts I worked around. No matter how much you hate being in the military, you still VOLUNTEERED, and that puts just the slightest amount of drive into you.
Above all that, no federal body should have the ability to force anyone to train and/or fight.
Exactly, I've trained a lot of foreign conscripts and maybe one out of a hundred was worth the effort and then even that one was only mediocre at best.