Dugin is widely viewed as chief ideologist for the hawkish wing of Russia's ruling elite, and his persistent influence inside the Kremlin has been widely documented.
Why is there no definite nor indefinite article in front of chief ideologist to denote that he is either just one of many chief ideologists, if there are more than one of them (indefinite article), or the to denote that he is the one and only chief in charge (definite article)?