The problem with these arguments is that they ignore the very personal moral issue/dilemma of when, under what conditions and how one should support his/her country's democratically mandated responsibility to provide for the common defense or carry out foreign policy. I'm not arguing about specific instances mentioned (Russia, Vietnam, Iraq, Afghanistan, etc, etc).  The fact is that each occurrence requires a moral decision on the part of the potential soldier. The easiest decision to make is one to obey - even at the risk of death or participation in an event one considers immoral.  

As pointed out, one may frequently make personal decisions about traffic laws (to obey or not obey) without major consequence, but a decision to ignore a lawful order during military duty (or even to fail to report for military duty as when conscripted) cannot be taken so lightly. One may argue that the lawfulness of such orders is determined by whether or not the order is legal and proper under the law, and this is true, but the burden to prove that the order was illegal can be heavy one. Usually, acts of war are only questioned when a country initiating them is defeated and held accountable by a victorious foe.  Merely disagreeing with the decisions (or as pointed out above claiming ignorance) imposed by court or democratically elected authority is obviously not a defense. Conscientious objection has sometimes been used successfully in the US to avoid participation in military action, but this must also be justified.

The other side of the question is the morality of ignoring a peacekeeping role during immoral wars.  For example, when should one take personal action to stop a conflict involving genocide.  Is it immoral to talk and negotiate endlessly while whole populations are being wiped out? If one found himself a soldier under UN orders in Bosnia, powerless to stop the ethnic cleansing, when would it be morally permissible to refuse to serve under the UN mandate? When was it morally acceptable to serve under NATO orders in Bosnia? Was it OK for NATO to bomb Serbian/Rep Serpska positions, etc.?

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears