Came across people with no leader finding support (10)
I believe the answer is:
foundation
'support' is the definition.
(I know that foundation is a type of support)
'came across people with no leader' is the wordplay.
'came across' becomes 'found' ('find' can be a synonym of 'come across').
'people' becomes 'nation'.
'with no leader' means to remove the first letter.
'nation' with its first letter taken away is 'ation'.
'found'+'ation'='FOUNDATION'
'finding' acts as a link.
(Other definitions for foundation that I've seen before include "Establishment" , "charity, say" , "cosmetic aid?" , "Base" , "Construction on which to build" .)