Alliances are reforming around borders of older disputed territory (6-8)
I believe the answer is:
alsace-lorraine
'disputed territory' is the definition.
The definition suggests a singular noun which matches the answer.
'alliances are reforming around borders of older' is the wordplay.
'reforming' is an anagram indicator.
'around' means one lot of letters goes inside another.
'borders of' means to remove the middle letters.
'older' with its centre removed is 'or'.
'alliances'+'are'='alliancesare'
'alliancesare' anagrammed gives 'alsacelraine'.
'alsacelraine' enclosing 'or' is 'ALSACE-LORRAINE'.
Can you help me to learn more?
(Other definitions for alsace-lorraine that I've seen before include "French region, lost 1871" , "border area" .)