More importantly, this is yet another example of where Turnbull has been at odds with an Abbott position that has hurt the government. How will he respond? Communications Minister Malcolm Turnbull. Credit:Alex Ellinghausen The Communications Minister's discomfort was plain to those who took part in the 5½-hour debate and reflected in his sarcastic observation that it would be "a great look" if the outcome forced ministerial resignations. If there was one thing he had learnt during his time as Liberal leader, Turnbull remarked during his contribution, it was the importance of keeping the team together. It was Abbott who counselled MPs at the outset that they would be able to defy a decision to deny them a free vote on marriage equality and cross the floor, so long as they were not in the executive.

But it was Senator Eric Abetz who reminded his colleagues that he had stepped down from the frontbench when confronted with a position he could not accept. Communications Minister Malcolm Turnbull after speaking to the media. Credit:Alex Ellinghausen This was in November 2009, when Abetz and five others (including Abbott) quit Turnbull's frontbench after they refused to back Turnbull's support for an emissions trading scheme, prompting the implosion of Turnbull's leadership. Now Turnbull has to decide whether he will be bound by the decision to stick with marriage being defined exclusively as the union between a man and a woman. Leadership rivals Prime Minister Tony Abbott and Communications Minister Malcolm Turnbull. Credit:Andrew Meares

Of course, other frontbenchers who spoke in support of marriage equality are in the same position, but Turnbull is the target of hard-line conservatives in the party who believe they have had a big win. "They want his scalp," is how one MP expressed it. One certainty, if there is a vote, is that Turnbull will not give them that satisfaction. During his contribution, Turnbull reminded his colleagues of how far behind the government was in the published polls to make the point that this debate would only make its position worse. "We are the party of the conscience vote," he told his colleagues. "It's in our DNA." Abbott can be satisfied that both the debate and the outcome keep faith with his pre-election statements. As he told me in May 2013: "It will ultimately be a matter for the post-election party room if it comes up, but I am strongly opposed to any change and I imagine that a strong majority in the Coalition party room will remain opposed to any change."

Where it deviates is in the mechanism for dealing with the issue in the future. Having declared in May that the issue ought to be "owned by the Parliament", he is now canvassing a plebiscite after the next election, assuming the Coalition is returned. "I did say that - and certainly that was my instinct at that moment - but obviously the party room has been thinking about this," Abbott explained on ABC Radio on Wednesday morning, adding that he was persuaded by the arguments put by a number of speakers in Tuesday's party room debate. The most persuasive advocate of a plebiscite was Foreign Minister Julie Bishop, but the prospect of a plebiscite after the next election means the issue will be prominent at the next election and after it, in the unlikely event that the Coalition wins. How does this help Abbott? Abbott's problem is all the greater because supporters of marriage equality don't trust him to deliver a process that will reflect community sentiment. And when would the plebiscite be held? In conjunction with the referendum on Indigenous recognition? These questions have not been canvassed because cabinet has never discussed the issue.

Here, writ large, is the question of judgment. Had Abbott supported his MPs having a free vote, he would have avoided the spectre of a split cabinet and seen the issue resolved, one way or the other, so he could focus on growth and jobs. For Turnbull, this is just another example of a contentious issue where he has differed from his leader and the hardline conservatives among his colleagues. Others include Abbott's portrayal of the threat posed by Islamic State, the citizenship debate, the war with the ABC and Q&A, and, one suspects, the failure to act sooner on Bronwyn Bishop. Loading Ultimately, if the government's standing does not markedly improve, he has a big decision to make.