The Civil Irregular Defense Group (CIDG) was a US Sponsored local milita organization 
created in South Vietnam.  The purpose of the CIDGs were to provide protection for so-called 
"fortified hamlets" and special force camps, as well as, to harass the Viet Cong and patrol 
the countryside.  These units were under direct US control through the Military Assistance Command Vietnam (MACV).
The CIDG program was transfered to the South Vietnamese government at the end of 1970.
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When this transfer occured, the CIDG elements were converted into new Ranger Border Defense Battalions.
The animosity between low-land ethnic Vietnamese and the various highland mountain tribes
of Vietnam meant that the capability of RBD units was questionable at best, because of an unwillingness
to fight for their new Vietnamese leaders.