Everyone in Republican Party in speedy action (6)
I believe the answer is:
gallop
'speedy action' is the definition.
'gallop' can be an answer for 'action' (gallop is a kind of action). I am not certain of the 'speedy' bit.
'everyone in republican party' is the wordplay.
'everyone' becomes 'all' (all people).
'in' indicates putting letters inside.
'republican party' becomes 'GOP' (the Grand Old Party, nickname for US Republicans).
'all' going within 'gop' is 'GALLOP'.
'in' is the link.
Can you help me to learn more?
(Other definitions for gallop that I've seen before include "Fast gait of a horse" , "Fastest run of a horse" , "Fast speed of horse" , "Faster than a canter" , "'Run at a high speed, like a horse (6)'" .)