'All in at election after touring', as country's leader once reputedly said (1,6,4,1,3)

I believe the answer is:

i cannot tell a lie

'as country's leader once reputedly said' is the definition.
(supposed George Washington quotation)

'all in at election after touring' is the wordplay.
'after touring' is an anagram indicator.
'all'+'in'+'at'+'election'='allinatelection'
'allinatelection' anagrammed gives 'I CANNOT TELL A LIE'.

I've seen this clue in The Guardian.

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