Touch of caution's gripping socialist leader (6)
I believe the answer is:
caress
'touch' is the definition.
(caress is a kind of touch)
'caution's gripping socialist leader' is the wordplay.
'caution's' becomes 'cares' ('care' can be a synonym of 'caution').
'gripping' indicates putting letters inside.
'leader' says to take the initial letters.
The first letter of 'socialist' is 's'.
'cares' placed around 's' is 'CARESS'.
'of' acts as a link.
(Other definitions for caress that I've seen before include "Pat" , "Stroke fondly" , "pet" , "Gentle affectionate stroking" , "Stroke lovingly" .)