In just seconds, American politician's polling is low (3)
I believe the answer is:
moo
'is low' is the definition.
(both can mean to make the noise of a cow)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for moo that I've seen before include "Guernsey noise?" , "Bovine low" , "Farmyard sound" , "Irritating woman" , "Cow's low" .)