Marty Harris is the Lowy Institute's Assistant Digital Editor.
In response to Malcolm Cook's post on Zombie-like international institutions, we received the following comment on Twitter:
Initial research suggests that @l_a_n_o_x is correct. At the time of the 1972 federal election, Labor Party policy (PDF; p.4) advocated that Australia 'should withdraw immediately from existing defence pacts such as SEATO', and a couple of weeks before the election Liberal Prime Minister William McMahon stated that, should Labor win the election, it would 'abandon SEATO'.
In October 1973, Prime Minister Whitlam confirmed in parliament that Australia had withdrawn from that year's joint SEATO military exercises. However, in February-March 1975 two Australian naval vessels participated in SEATO exercises in the South China Sea, and in September of that year the Labor Government's foreign minister Don Willessee attended a SEATO Council meeting in New York, noting on his return that the meeting had decided to phase out SEATO in an 'orderly and systematic matter'. This was of course after the fall of Saigon to North Vietnamese forces at the end of April 1975.
Interestingly, it does not appear that Australia sent any military personnel to participate in SEATO's final joint exercise, held in the Philippines in February 1976. The organisation was formally disbanded in June 1977.