Government, say, obstructs the return of Arab ruler (6)
I believe the answer is:
regime
'government' is the definition.
(I know that regime is a type of political system)
'say obstructs the return of arab ruler' is the wordplay.
I cannot really see how this works, but
'say' could be 'eg' (short for 'exempli gratia', 'for example' in Latin) and 'eg' is found in the answer.
'ruler' could be 'r' (r is abbreviation regina. e.g. in ER ) and 'r' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for regime that I've seen before include "Command" , "Authoritarian system" , "Prescribed course" , "Government, especially an authoritarian one" , "Governing authority or therapy plan" .)