Call from Democrat opposing the President? (2-5)
I believe the answer is:
no-trump
'call from democrat' is the definition.
The definition suggests a singular noun which matches the answer.
'opposing the president?' is the wordplay.
'opposing' becomes 'no' (I can't justify this - if you can you should give a lot more credence to this answer).
'the president?' becomes 'trump' (Donald Trump).
'no'+'trump'='NO-TRUMP'
Can you help me to learn more?
(Other definitions for no-trump that I've seen before include "The kind of contract" , "possible contract" , "Put morn (anag.); bridge call" , "Having no suit ranking above all others" , "that many left-wing Americans desire?" .)