Ready to drop, tried pushing Republican back (5)

I believe the answer is:
tired
This could be a double definition.
'ready to drop' is the first definition.
(I've seen this in another clue)
'tried pushing republican back' is the second definition.
Both the definition and answer are adjectives. Perhaps there's a link between them I don't understand?
Can you help me to learn more?
(Other definitions for tired that I've seen before include "Whacked" , "Weary, jaded" , "Physically or mentally weary" , "Done in" , "Zonked" .)
