Battle for the high ground on the border (8)
I believe the answer is:
edgehill
'battle' is the definition.
(I've seen this before)
'high ground on the border' is the wordplay.
'high ground' becomes 'hill' (I've seen this before).
'on' says to put letters next to each other.
'the border' becomes 'edge' (synonyms).
'hill' after 'edge' is 'EDGEHILL'.
'for the' acts as a link.
(Other definitions for edgehill that I've seen before include "battleground" , "First battle of the Civil War, 1642" , "Eng. Civil War battle" , "Battle of the English Civil War" , "where battle was fought" .)