Try to get support for having a gate put outside it (7)
I believe the answer is:
agitate
'try to get support for' is the definition.
I can't tell whether this defines the answer.
'a gate put outside it' is the wordplay.
'put outside' means one lot of letters goes inside another.
'gate' placed around 'it' is 'gitate'.
'a'+'gitate'='AGITATE'
'having' is the link.
Can you help me to learn more?
(Other definitions for agitate that I've seen before include "Trouble, make nervous" , "Stir; arouse" , "cause trouble" , "Upset, disturb the surface of" , "Disturb or stir up" .)