Until the advent of the 24/7 news cycle, there was no clear role for former political leaders, including prime ministers. Now, quite a few become media commentators. Most support the political parties they once led – but not all.

During the 2010 election, former Labor leader Mark Latham used his role as a 60 Minutes presenter to call on all electors to vote informal and to refrain from supporting either Julia Gillard or Tony Abbott.

Last Friday, former Liberal Party prime minister Malcolm Fraser sent out a tweet calling on Australians to “vote Green in Senate” since he does not want either Labor or the Coalition to get a majority in the Senate and the House of Representatives.

Fraser has gone one step beyond Latham in that he is advancing the cause of the Greens, once a rival party, in the Senate. On the same day, Labor MP Chris Bowen wrote in his column in The Spectator Australia that these days Fraser “sounds like a Greens candidate for the Senate”.

When Fraser resigned from Parliament after losing the 1983 election, he said that he did not propose to become a commentator on Australian politics. Yet, over the past three decades, he has become precisely this.

Last week, Fraser got front-page coverage in the NT News, and a report in The Guardian, for his claim, in a speech, that the United States could launch a military attack from Darwin using the marines who are based in the city for six months each year. The speech was made at Melbourne University, which gives Fraser a platform for his numerous entries into Australian politics.

Latham's involvement in politics is frequently an irritant for Labor, but he has little standing. Latham led Labor to a disastrous defeat in 2004. His prime electoral bribe was the massively underfunded and non-means tested Medicare Gold, which would have provided free healthcare in public and private hospitals for everyone aged 75 and older. Also, Latham's erratic behaviour before, during and after the 2004 election left him diminished in the credibility stakes.

Not so Fraser. He led the Coalition to victories in 1975, 1977 and 1980 and is a significant figure in Australian political history. As a former prime minister, Fraser has – and deserves – standing. This is why his stance in recent years on foreign policy and national security – which is to the left of Labor and close to the Greens – deserves scrutiny.

In a recent interview with Labor Party historian Troy Bramston in The Weekend Australian, Fraser pointed to his achievements in such areas as “freedom of information laws, the Ombudsman, refugee policies, multiculturalism … [and] the Human Rights Commission”.

He added that “all of those things were entirely consistent with what I've been saying since leaving politics”. This is true. Fraser has been a long-time supporter of environmental issues and indigenous causes.

However, he has changed his views dramatically on foreign policy and national security. Fraser was once one of the leading proponents of the Australia-US alliance – during and after Australia's military commitment in Vietnam. He was also a staunch anti-communist who supported the tough national security legislation introduced by Robert Menzies' Coalition government in the 1950s and early 1960s.

Now Fraser regards Australia as a hostage to the US. He maintains that the small US presence for six months a year in Darwin, which will eventually increase to 2500 marines, could be used by the US to launch military attacks on (unspecified) Asian nations without the knowledge of the Australian government.

This is fantasy. Here Fraser is opposed to the foreign policy stances of both Labor and the Coalition but is close to that of Senator Christine Milne and the Greens.

His autobiography Malcolm Fraser: The Political Memoirs (which he co-wrote with left-wing academic Margaret Simons) is replete with factual errors and convenient omissions. Yet, it is telling, nevertheless. Towards the end of the book, it is recorded that, these days, Fraser receives applause at literary festivals “by the same kinds of people who had once reviled him”.

Fraser, who resigned from the Liberal Party in 2009, has offered to counsel Abbott if he becomes prime minister. He claims he “never had any cross words” with the Liberal Party leader. Yet, in October 2011, when interviewed by Robyn Eckersley for The Conversation, Fraser agreed with the proposition that Abbott is dangerous, criticised his unpredictability and declared that “the whole party is very much to the extreme right”.

If the Coalition defeats Labor, it seems likely that Fraser will remain a Liberal Party critic. This will keep him in the media and will delight the green-left types who frequent taxpayer subsidised literary festivals.

Gerard Henderson is executive director of The Sydney Institute.