Judge an American god (5)

I believe the answer is:

janus

'god' is the definition.
(Roman god)

'judge an american' is the wordplay.
'judge' becomes 'j'.
'american' becomes 'us'.
'j'+'an'+'us'='JANUS'

(Other definitions for janus that I've seen before include "Roman god of doors and beginnings" , "Roman god of doors, usually two-faced - a month is named for him" , "Two-faced person" , "Two-faced god of gates and doors - Guardian cryptic crossword setter" , "Two-faced deity" .)

I've seen this clue in The Guardian.

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