I see a guru as a transitional object.  It is not the person that is a guru, but rather the guru role is thrust upon him or her through the emptiness that is available when one has fallen free of personal conditions.  This role can be used freely by those students who are seeking the understanding of their true nature until they are ready to find the guru within --  their own direct connection with inner wisdom, unconditional love and a liberated life, free of old patterns and conditioning.  When this inner realization is known there is a deep relaxation of the mind, so that inner judgment and preoccupation with the senses fall away, leaving a quiet presence and openness that allows others to feel a  transmission of peace.