The spirit of the League motto was enunciated as far back as the fourth century BC in the Greek Demosthenes Philippic 2, section 24:
'There is one safeguard known generally to the wise, which is an advantage and security to all, but especially to democracies as against despots. What is it? Distrust.'
The words chosen by the League appear to have been first spoken by John Philpot Curran on his election as Lord Mayor of Dublin in 1790. Curran said:
'It is the common fate of the indolent to see their rights become a prey to the active. The condition upon which God hath given liberty to man is eternal vigilance; which condition, if he break, servitude is at once the consequence of his crime and the punishment of his guilt.'
In 1852, Wendell Phillips used the expression 'Eternal vigilance is the price of liberty' in an address to the Massachusetts Anit-slavery Society. Apparently, the phrase was subsequently attributed to Thomas Jefferson, but Phillips argued this was incorrect, that the phrase had never been found in Jefferson's works.
Whether any of these quotations motivated someone to adapt the words to those that became the League motto, or whether someone suggested the motto in the belief that it was original is unknown.
The League did not have a motto until 1923. In 1922 the Victorian Branch recommended to the National Executive that there should be a motto. Memos sent to each State on the matter drew no response. At the eighth National Congress held in Hobart the following year, however, the New South Wales Branch moved that the motto be 'The Price of Liberty is Eternal Vigilance', which was accepted and has been the League motto ever since.
No evidence has emerged explaining who made the suggestion to the New South Wales Branch or how the form of words evolved.