You are talking about liberal democracy, right? Because regular democracy doesn't contain this important bit.
However, even in case of liberal democracy, there is exception from the rule in case of war, because SOMEONE WILL DIE ANYWAY.
If you think that liberal government cannot send a men X to the front line, then government must sent a men Y, or accept that woman or children Z will die. Someone will die anyway. Moreover, if the men Y sent to front line where he can die from enemy action, or woman or children Z dies from enemy action, why the men X should be exempt from that?
However, even in case of liberal democracy, there is exception from the rule in case of war, because SOMEONE WILL DIE ANYWAY.
If you think that liberal government cannot send a men X to the front line, then government must sent a men Y, or accept that woman or children Z will die. Someone will die anyway. Moreover, if the men Y sent to front line where he can die from enemy action, or woman or children Z dies from enemy action, why the men X should be exempt from that?