From SuspireWiki

(n., informal) The reach and limits of one’s will as projected by the supernatural power of Ventrue blood (q.v.). This refers not only to a measure of physical range, but also a roster of subjects, contacts, and other targets being manipulated with Dominate, as well as the efects of the Discipline in general.

If you get in that car with him, he’ll have you in his dominion inside of ten minutes.