driving force

[Anatoly]

Hello, dear teachers & members!
Could you explain to me what is meant by “driving force” in the following sentence:
“Thomas is the driving force behind the Towerhill Flat Dweller’s Association, which has campaigned for years to have the flats evacuated.”?
Thanks in advance!

[Red5]

driving force
The impetus, power, or energy behind something in motion, as in He was clearly the driving force in the new administration. This term transfers the force that sets in motion an engine or vehicle to other enterprises. Ralph Waldo Emerson was among the first to use it figuratively (English Traits, 1856): “The ability of its journals is the driving force.”

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The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.

[Tdol]

The driving force is the person, etc, who is the main motivator and organiser of something. They might not actually be in charge, but it is their effort and enthusiasm that is vital.

[Anatoly]

Thank you very much, Red5 and Tdol, for your explanations! Now it's clear for me completely. :D

[Tdol]

You're welcome.