Julia Gillard was abandoned by colleagues who bore her no animosity in 2013. Will the same happen to Tony Abbott as his backbench becomes increasingly nervous? Norman Abjorensen writes.

A recurring theme among Liberals as they ponder the dismal polls and the error-prone judgments of the man at the helm is that they do not want to be seen resembling Labor by deposing their leader - and a first-term prime minister at that.

The implications of this are cold comfort for Tony Abbott: one is that there is a widely-held belief that he should go; two is that he has Kevin Rudd, Julia Gillard and the ALP to thank for the fact that he still holds his job.

Just how similar are the two sets of circumstances?

Down in the polls

Both Rudd and Gillard were deposed when their polling started to go into free fall and their prospects of winning the looming election began to recede by the day.

Tony Abbott has languished in the polls for much of his term since soon after winning the 2013 election, but the latest trend - coming on top of the Bronwyn Bishop saga, the marriage equality fiasco and the Dyson Heydon imbroglio - has opened up the gap.

The weekend IPSOS poll recorded a swing against the government in voting intentions that would cost it 36 seats if an election were held now.

And this comes after a soft, electorate-friendly budget designed to claw back support and a Royal Commission designed to inflict damage on Opposition Leader Bill Shorten who, thanks to Abbott's waning approval rating, is now the clearly preferred prime minister.

This was not how the script was written.

Nervous backbench

With an election due within the next 14 months - and all prospects of an early poll having now vanished - the backbench is increasingly nervous, and none more so than those members sitting on slim margins.

Just as Julia Gillard was abandoned by those who bore her no animosity in 2013, self-interest prevailed over principle and loyalty as a scramble for survival ensued.

Both Rudd and Abbott were fond of the "captain's call", and in each case exposed their political judgments as flawed: Rudd over his abandoning of the Emissions Trading Scheme (ETS) in which he had invested much political capital and Abbott over his knighting of Prince Philip; appointment of Bronwyn Bishop as speaker, and the subsequent defence of her indefensible travel expenses; and the refusal to allow a free vote - very much a part of Liberal tradition - on the issue of marriage equality.

A further complicating factor in Rudd's floundering first prime ministership was a widespread, and growing, personal dislike of him - an issue that does not trouble Abbott, who is personally liked by his colleagues, even those who doubt his capabilities.

The legacy of the 2007 election

In a sense, the current doubts surrounding the Liberal leadership are not so much new as revived, and can be traced back to the 2007 election defeat, John Howard's loss of his seat, Peter Costello's unexpected retirement, and a lack of clear succession.

The ineffectual Brendan Nelson, the ambitious Malcolm Turnbull and the even more ambitious Tony Abbott came and went through a revolving door within the term of a single parliament - a fact that Labor could have made more of.

Tony Abbott, despite his resounding win in 2013, has never been entirely secure; many in his own team have continued to harbour grave reservations about his leadership qualities, especially in regard to political judgment. He has always been a divisive figure.

After serving as a minister in the Howard government, Abbott made some soundings about a possible leadership run after Howard lost his seat in 2007, but he found little support among his colleagues.

At the end of 2009, Abbott wrested the leadership from Turnbull after having resigned from the frontbench in November in protest against Turnbull's support for the Rudd government's Emissions Trading Scheme.

The circumstances of that leadership change are worth revisiting. Turnbull had been left largely isolated in his party - and was being actively undermined - over his support for the ETS. The conflict came to a head in December 2009, when 48 MPs, a clear majority, voted for a spill.

In a three-way ballot, Tony Abbott topped the list with 35 votes, short of an absolute majority; Turnbull won 26 votes and Joe Hockey 23. Of Hockey's tally, seven went to Abbott in the run-off, 15 to Turnbull, and one was informal.

What was remarkable was the fact that Abbott won the final ballot 42 to 41, meaning that of the 48 who voted for the spill, seven reverted to Turnbull when faced with the prospect of an Abbott victory. One Liberal, later a senior minister, seemed to speak for many in the party when he told me that the prospect of Tony Abbott as Prime Minister was "a very sobering thought".

Against the odds journey to the Lodge

Abbott proved to be an aggressive opposition leader and there is little doubt that he created trouble for then prime minister Kevin Rudd, whose popularity was in decline, and who would be deposed the following June, just months out from the election.

Abbott fought a strong campaign which saw Labor lose 11 seats, but the outcome was a hung parliament.

Ordinarily, Abbott's failure to secure a clear victory should have cost him his job, if past precedents were a guide, but he defied the trend. He again failed when he was unable to coax the key independents, who held the balance of power, to support a Coalition government in the hung parliament.

Some polling pointed to Abbott himself as a key factor in the election result; certainly he was instrumental in the decision by two conservative independents to support Labor.

Although a winner in 2013, it has been a rocky road for Tony Abbott, who has won over neither the majority of the people nor all of his party, and doubts about his leadership have persisted. His own self-described 'near death' experience in February when 39 of his 100-member party room voted for a spill despite there being no challenger extracted from him a pledge for "good government", and, by implication, a lift in the polls. Neither has eventuated.

Some superficial similarities exist with the Labor leadership upheavals - notably dismal polls - but far more important in the current situation is Tony Abbott himself, who has always had his doubters, who may well be right about him.

Dr Norman Abjorensen, of the ANU's Crawford School of Public Policy, is the author of three books on the Liberal Party and its leaders. His book The Manner of Their Going: Prime Ministerial Exits in Australia will be published next month by Australian Scholarly Publishing.