Is and isn't organising protests (3-3)
I believe the answer is:
sit-ins
'protests' is the definition.
(sit-in is a kind of protest)
'is and isn't organising' is the wordplay.
'and' says to put letters next to each other.
'organising' is an anagram indicator.
'is'+'isnt'='isisnt'
'isisnt' is an anagram of 'SIT-INS'.
(Other definitions for sit-ins that I've seen before include "In these protests, demonstrators refuse to leave a building" , "Obstructive protests" , "Forms of civil disobedience in which demonstrators refuse to leave a building" .)