Speak about Democrat and Liberal with regret (5)
I believe the answer is:
sadly
'with regret' is the definition.
(I've seen this before)
'speak about democrat and liberal' is the wordplay.
'speak' becomes 'say' (I've seen this before).
'about' indicates putting letters inside.
'democrat' becomes 'd'.
'and' says to put letters next to each other.
'liberal' becomes 'l' (abbreviation).
'd'+'l'='dl'
'say' placed around 'dl' is 'SADLY'.
(Other definitions for sadly that I've seen before include "Unhappily" , "With sorrow" , "Alas" , "Lamentably, unfortunately" , "I regret to say" .)