To assume or accept a subordinate position; demote or degrade oneself: He said he wouldn't take a back seat to anybody but the president himself(1888+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with take a back seat
Occupy an inferior position; allow another to be in control. For example, Linda was content to take a back seat and let Nancy run the meeting. This idiom uses back seat in contrast to the driver's seat, that is, the one in control.