Contractors versus Mercenaries

There have been a number of civilian contractors killed in Iraq and Afghanistan.  I wonder if there is ionformation breaking them down by vendor and by job title.  A road builder or an electrical engineer has a job that is qualitatively differnt from a team leader in a heavy weapons squad of mercenary security personnel.  If soldiering is in the job description, why do American newspapers call these people "contractors?"  Is it a Tony Soprano thing?  Are we that inured to mob speak that we understand that "having a contract" means sealing someone’s doom?  That couldn’t be it.  Could it? Bush, Rove, Cheney, Rumsfeld, and the neocon chickenhawks are all thugs at heart, but do they talk that way?  And have they influenced the media to talk that way?  Let’s call a mercenary a mercenary.