A little under a million years ago, the briny waters of the Baltic Sea began flooding into the cold North Atlantic: geologists are still debating ____
(a) about whether the flood was gradual or cataclysmic.
(b) whether the flood was gradual or cataclysmic.
Which option is correct and why?
Best Answer
This question has in fact been asked on ELU. It didn't generate a lot of interest, but as my answer there shows, debate isn't usually followed by about in such constructions (I personally don't like the usage).
The relevant usage figures from Google Books are they debated whether [to do something]: 11,700 hits, but "they debated about whether" gets only 87. So go with the vast majority - don't include "about".
As to the reason, I think it really comes down to established idiomatic preference. Possibly influenced by the fact that discuss is syntactically very close to debate (in which context it's worth noting that they discussed about whether gets only 2 hits, compared to 35,900 for they discussed whether).
To my mind, debate and discuss both equate to talk about, so the word about is already implied anyway.