Yeah, but…
if your sergeant told you, arbitrarily, to jump off a bridge, would you do it? I mean, conscience still has to have some role to play, doesn’t it? Is “I was just following orders” a completely bulletproof moral excuse?
My answer would be-- it depends on how certain the soldier is of the unjust nature of the war, and on how reasonable that certainty is. If you’re pretty darn sure that the war is wrong, I’d say you’ve got to lay down your arms. But the benefit of the doubt goes to your legitimate and hopefully well-informed civil leadership.