TASS long spreading Gorbachev initiative (8)
I believe the answer is:
glasnost
'gorbachev initiative' is the definition.
(I've seen this before)
'tass long spreading' is the wordplay.
'spreading' indicates anagramming the letters.
'tass'+'long'='tasslong'
'tasslong' is an anagram of 'GLASNOST'.
(Other definitions for glasnost that I've seen before include "Gorbachev initiative" , "Policy of openness under Gorbachev" , "Openness (Russian)" , "Gorbachev's policy from 1985" , "Gorbachev's policy of "openness"" .)