The most common and most likely answer to this crossword clue is the 6 letter word CONFER
I've seen this crossword clue in Independent
C
O
N
F
E
R
Buddy explains!

The straight part
We know that "debate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case debate = confer.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CONFER mean?
CONFER verb- To grant as a possession; to bestow.
- To talk together, to consult, discuss; to deliberate.
- To compare.
- To bring together; to collect, gather.
- To contribute; to conduce.