Those circumstances contributed to the 1975 Australian constitutional crisis, which culminated in the dismissal of the Prime Minister, Gough Whitlam, by the Governor-General, Sir John Kerr.

As trade-union adviser on the Australian delegations, he travelled to Geneva to attend the thirty-seventh (1954) and forty-eighth (1964) sessions of the International Labour Conference.

An active and influential State party manager, he chaired the rules committee, held office as vice-president for a term, and was president in 1963–68.

[1] Milliner was a competent chairman who tried to achieve unity, to broaden the party's electoral base, and to encourage the involvement of women and the young.

His leadership proved decisive in winning party support in Queensland for Gough Whitlam in his confrontation with Labor's federal executive in February 1966.

[1] In 1962 Milliner had unsuccessfully sought party nomination to be considered by the Legislative Assembly of Queensland for a casual vacancy in the Senate following the death of Max Poulter.