On Sky News last week, Tim Costello declared his (political) love for Malcolm Turnbull. It was all very touching – and all very well. Except the head of World Vision Australia is not – and has never claimed to be – a Liberal Party supporter. Rather, Costello has invariably taken a position on the centre-left in the domestic political debate.

Tony Abbott was correct in appointing Turnbull to the shadow cabinet with responsibility for communications and broadband. Turnbull has the business acumen and technical expertise to critique the taxpayer funding of Labor’s monopolistic national broadband network.

But an appointment to the shadow cabinet entails an understanding an individual will abide by collective decisions, irrespective of his or her personal position. Collective responsibility encompasses support or silence. Public disagreement should be accompanied by resignation from the ministry or shadow ministry. There is an understanding those appointed as ministers or shadow ministers will speak, for the most part, on their area of responsibility.

So far, Turnbull has not followed traditional protocols. Last week, following the calls of BHP Billiton‘s chief executive, Marius Kloppers, for a carbon tax, Turnbull went into tweet mode. On Wednesday, he described Kloppers’s address as “very thoughtful”. The next day Turnbull tweeted his support for an emissions trading scheme or a carbon tax and indicated his lack of enthusiasm for reducing carbon emissions by regulation – the Coalition’s policy. Turnbull spoke out about his climate change opinions on Radio National.

These comments excited Costello, among others. But the fact remains Turnbull lost the Liberal Party leadership last December because a majority of his colleagues disagreed with his support for Rudd Labor’s proposed emissions trading scheme. After Abbott defeated Turnbull by one vote, Abbott moved a motion on the ETS drafted by Kevin Andrews. In a secret ballot, MPs supported Abbott’s opposition to the legislation by 54 to 29 votes.

In other words, Turnbull had been trying to force through the party room legislation opposed by two-thirds of his colleagues. The Nationals were also against an emissions trading scheme, so in any joint meeting of the Coalition, some three-quarters would have disagreed with Turnbull’s position. Any leader would need more political skills than Turnbull has to prevail in the face of such opposition.

Turnbull misread his party and misjudged the electorate. In the weekend before the leadership ballot, Turnbull was interviewed by Laurie Oakes on Sunday. In an extraordinary outburst, Turnbull declared if the Liberal Party opposed an emissions trading scheme it would be “destroyed by Kevin Rudd in an election” and would suffer “an electoral catastrophe”.

Within less than a year, Rudd had been sacked and Labor, under the leadership of Julia Gillard, became the inaugural first-term government since 1931 not to be re-elected in its own right. The Coalition’s two-party preferred vote was highest in the states where mining is most important such as Western Australia and Queensland.

Last year, when Turnbull was leader, the Coalition was conceding it would lose at least 20 seats in the election. Under Abbott, the Coalition got as close as it possibly could to winning. Yet Turnbull seems to believe his colleagues should follow his support for an emissions trading scheme or a carbon tax, irrespective of the stance taken by the US, China and India.

Certainly Turnbull did very well in his seat of Wentworth, with a swing of 11 per cent of the two-party preferred vote. This partly reflected the support he received from former Labor supporters. Yet it should be remembered Joe Hockey obtained a 9 per cent swing in North Sydney – and he was a senior member of the opposition who did not publicly distance himself from his leader on climate change.

Turnbull, on a good day, is a plus for the opposition. Yet his policies on climate change – and his socially progressive beliefs documented in Annabel Crabb’s essay Stop At Nothing – are far from popular in the outer suburbs and regional areas where most marginal seats are located.

Turnbull may become a team player. Or he may become yet another Liberal who spends much time criticising the party he once led – in the tradition of the late John Gorton, Malcolm Fraser and John Hewson. They are the kind of Liberals whom Tim Costello loves.