to be in a position where you have power or control over sb/sth
HAVE / HOLD, ETC. THE WHIP HAND (OVER SB/STH)
Meaning of HAVE / HOLD, ETC. THE WHIP HAND (OVER SB/STH) in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005