Recession can be a small piece of luck for politician (5)
I believe the answer is:
slump
'recession' is the definition.
(I've seen this before)
'a small piece of luck for politician' is the wordplay.
'a small' becomes 's' (abbreviation - e.g. clothes size).
'piece of' says to take the initial letters.
'for politician' becomes 'ump' (I can't explain this - if you can you should give a lot more credence to this answer).
The initial letter of 'luck' is 'l'.
's'+'l'+'ump'='SLUMP'
'can be' acts as a link.
Can you help me to learn more?
(Other definitions for slump that I've seen before include "Deep recession" , "Sudden drop in business" , "Sudden fall as in share values" , "Sudden decline" , "Economic depression" .)