US city making contribution to help a soldier (2,4)
I believe the answer is:
el paso
'us city' is the definition.
(I've seen this before)
'contribution to help a soldier' is the wordplay.
'contribution to' indicates the answer is hidden within the clue.
'EL PASO' is hidden within 'help a soldier'.
'making' is the link.
(Other definitions for el paso that I've seen before include "Texan city" , "City of Texas on the Rio Grande; aslope (anag.)" , "city on Mexican border" , "West Texas town" , "US city" .)