Urge two universities to support Independent politician (7)
I believe the answer is:
impulse
'urge' is the definition.
(I know that urge can be written as impulse)
'two universities to support independent politician' is the wordplay.
'two universities' can mean two replacements for 'university'.
'university' becomes 'U' (abbreviation for university).
'university' becomes 'lse' (London School of Economics).
'to support' means one lot of letters go next to another (in a down clue, some letters hold others up).
'independent' becomes 'i'.
'politician' becomes 'MP' (Member of Parliament).
'u'+'lse'='ulse'
'i'+'mp'='imp'
'ulse' put after 'imp' is 'IMPULSE'.
(Other definitions for impulse that I've seen before include "A sudden urge or whim" , "I may cause desire" , "Chew" , "A push; whim" , "Instinctive motive" .)