Disheartened over a politician’s speechmaking (7)
I believe the answer is:
'speechmaking' is the definition.
(I've seen this in another clue)
'disheartened over a politician's' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters).
'politician' becomes 'tory' (term for a Conservative Party politician).
'over' with its middle removed is 'or'.
(Other definitions for oratory that I've seen before include "speech day's main feature?" , "Place for private prayer" , "Art of public speaking or small chapel" , "Art of speech" , "Small chapel for private worship" .)