Called on the services of American journalist? (4)

I believe the answer is:

used

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'called on the services' is the definition.
I can't tell whether this definition defines the answer.

'american journalist?' is the wordplay.
'american' becomes 'us'.
'journalist?' becomes 'ed' (short for editor).
'us'+'ed'='USED'

'of' acts as a link.

Can you help me to learn more?

(Other definitions for used that I've seen before include "Pre-owned" , "Hand-me-down" , "Accustomed - exploited" , "took a chance on becoming dependent" , "worked unfairly" .)

I've seen this clue in The Telegraph.

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