Republican slogan maybe is mad (7)
I believe the answer is:
barking
'is mad' is the definition.
(I've seen this before)
'republican slogan' is the wordplay.
I cannot quite understand how this works, but
'republican' could be 'r' (abbreviation in US politics) and 'r' is present in the answer.
The remaining letters 'baking' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'maybe' acts as a link.
Can you help me to learn more?
(Other definitions for barking that I've seen before include "Mental" , "What Battersea resident may be doing" , "Area of London - mad?" , "Mad - sound of a dog" , "Completely mad" .)