Topical reforms in American political scene (7)

I believe the answer is:
capitol
'american political scene' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'topical reforms' is the wordplay.
'reforms' indicates anagramming the letters.
'topical' is an anagram of 'CAPITOL'.
'in' is the link.
Can you help me to learn more?
(Other definitions for capitol that I've seen before include "government building" , "American Congress building" , "Roman temple" , "US Congress building" , "where state legislature sits" .)
