What makes you think that every person in charge at the Dept of Defence (not "Offense", or "War") is not a voice with a desire to provide a list of reasons why a pending decision about committing our volunteer service members to a war is a bad idea (if it is, indeed, a bad idea)? Why do you presume that the State Dept., the Defence Dept., the President, Vice-President, etc., etc., do not seek answers to other options prior to going to Congress (another whole "check and balance" you've neglected to discuss) to recommend going to war with someone?
Your list of questions makes no sense, when regarded with reality.