The Republic Troopers and Space Fleet easily overpower the separatists, using immense force and special ops forces.
However, a select type of robot, led by a hired mercenary sent by Count Dooku, makes mincemeat of the Republic forces in a sneak attack.
This mercenary, Durge, works for the Separatists mainly because he has a grudge against the Mandalorians, a race brought to extinction by the Republic in a brutal war hundreds of years ago ... but cloned to form the Republic Army and the lone survivor of the Mandalorians, Boba Fett.
Hired hands of terrorists, with grudges against Americans, striding onto the battlefield in Iraq and destroying our armies ... Yep, that sounds about right.