The most common and most likely answer to this crossword clue is the 12 letter word WARMONGERING
I've seen this crossword clue in The Daily Telegraph
W
A
R
M
O
N
G
E
R
I
N
G
More clues leading to the result WARMONGERING
Buddy explains!
The straight part
We know that "willing to be hawkish" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case willing to be hawkish = warmongering.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 WARMONGERING mean?
WARMONGERING verb- To advocate war.
- Bellicism; militarism