Christians in the military

  I got in a bit of a discussion today about whether a Christian may serve in the military.  This has been answered before by many people smarter than I using rationale such as God identifying Himself as a mighty warrior; His praise for David and Joshua, who were warriors; and the absence of condemnation toward soldiers by John the Baptist and Jesus when given the opportunity.  One of the arguments often given by those claiming Christians should not serve in the military is that the governmental authorities may use the military to do something unjust or immoral.  I grant that the occasion may arrive in which a Christian would have to choose to disobey military orders in order to stay true to Biblical principles.  However, I get annoyed with those who make a facile assumption that they know why a country is taking a particular military action. 
  Take as given for the moment that it is not prohibited for a Christian to serve in the military of a secular government (no prohibitions were given to the centurion who impressed Jesus or to Cornelius).  This government will make most of its decisions to employ the military using self-serving Machiavellian motivations, not generally God-honoring motivations as if it were a God-centered theocracy.  God's chosen people, Israel, weren't even able to stay true to God-honoring purposes in the use of their military.  There may occur moments when a nation will openly state wicked purposes for engaging in military action.  The military may be ordered to invade another nation to take possession of its land and to exterminate the population in the process.  That would be one of the more obvious cases where a Christian soldier would have to make a choice between his vocation and the God he serves.
  However, it is not usually that obvious, at least in the modern era.  In the case of two of the more maligned recent conflicts, Vietnam and Iraq, people like to glibly say they were about oil or money or whatever.  However, in both cases the stated reason was to neutralize a threat to the United States and to support and enable the local government (in Iraq that second reason came in after Saddam Hussein was deposed).  For the service member in the military, there is no obvious reason to object to the strategic mission.  Sure, we could all second guess various aspects and claim various hidden agendas but, really, we don't have sufficient evidence to go against our orders.  Then, military commanders at various levels could interpret or apply their mission in ways that contradict Biblical principles.  That could happen in business or other organization as well.  As members of a military unit, we know that if an immoral order is given, such as happened at Wounded Knee or My Lai, we have the right and the obligation to refuse the order and to report the incident.  In 99.9% of situations, the actions of American military, at least, are consistent with Biblical injunctions and what would be expected of being part of the sword wielded by the state.  Those that are not usually violate the law of war set forth in the Geneva Conventions and/or the Uniform Code of Military Justice and those individuals are punished.
  All that having been said, I am not happy with the direction the national government is currently headed and the implications that will have for the military.  I can imagine it will become more difficult in years ahead for a Christian to serve in the military in good conscience.  And if that happens the absence of salt and light can cause a downward spiral that is difficult to reverse.