What Liberal Democrat must be to be seen as moral and creditable? (10)

'creditable?' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs sometimes mean the same thing.

'what liberal democrat must be to be seen as moral and' is the wordplay.
I cannot quite understand how this works, but
'democrat' could be 'd' and 'd' is found in the answer.
'be' could be 'am' and 'am' is found within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is present in the answer.
'as' could be 'aa' (two letter A's) and 'aa' is found within the leftover letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?