I don’t see a problem hiring security personnel to protect VIPs. The military has other pressing matters in front of it, like killing the enemy, to be babysitting a bunch of suits.
I don't imagine that the US military has many units that are actually trained in the techniques of "personal protection". With Iraq you suddently had a huge demand for this type of work. Not saying that the US military couldn't assemble such units, but I don't think 'real soldiers' would want to serve as bodyguards. Just my 2 cents.