Responsible for underground movement going back on the road to Washington on Fourth of July (6)
I believe the answer is:
subway
'responsible for underground movement going back on the road' is the definition.
I can't tell whether this defines the answer.
'to washington on fourth of july' is the wordplay.
'to' becomes 'sub' (I can't explain this - if you can you should believe this answer much more).
'washington' becomes 'wa'.
'on' says to put letters next to each other.
'fourth of july' becomes 'y' (fourth letter of the word 'July').
'sub'+'wa'+'y'='SUBWAY'
Can you help me to learn more?
(Other definitions for subway that I've seen before include "Pedestrian way beneath a road" , "NY underground" , "US underground railway" , "New York underground" , "Underground rail" .)