In the last 24 hours Malcolm Turnbull has made extraordinary comments on Coalition policy and the Liberal Party leadership that must be addressed.

Remembering that Turnbull lost the Liberal leadership in late 2009, partly over the Godwin Grech fake email affair but mostly because of a revolt by his own MPs over the climate change policy he surrendered to Kevin Rudd over, these are unhelpful in the extreme. Yes, I write as a conservative, but for Turnbull to choose this point in time to recommence the airing of his views, and in so doing undermine Coalition policy and by extension the leadership of Tony Abbott, shows appalling political judgement.

Don’t forget, he crossed the floor of Parliament to vote against his Party’s ongoing policy on climate change as a backbencher following his loss of the leadership. Fair enough. He’s had his minute of defiance.

However, this latest outburst, in the context of his role as a senior Coalition shadow minister is, to use a Rudd phrase, a bridge too far.

The first point I would make is that Turnbull is shadow Communications spokesman, not shadow Environment spokesman, and as such he is bound by shadow cabinet decisions on issues relating to Coalition policy.

Further, he is not a member of the parliamentary leadership team, which limits his right to speak freely across a range of portfolios.

I note Turnbull isn’t making statements on immigration policy, or health policy, or industrial relations policy.

No, to make portentous, grandiose and inflammatory statements, always go for the hot button issue — climate change.

And “hot” the button is. Incendiary. Thus far, climate change policy has destroyed the leadership of former Liberal leader Brendan Nelson; it ultimately contributed fulsomely to destroying Kevin Rudd’s Prime Ministership; it will destroy Julia Gillard and the contender to succeed her, Greg Combet; and it contributed to the downfall of the Howard government (but from the “Johnny come lately” perspective there).

Whether you like it or not, whether you believe in climate change or not, one stark truth has emerged from Australian politics in the last three years: people may want to save the environment, and tackle this and that, but at the first sign of it costing a red cent from the back pockets of voters personally, support for the whole thing vanishes.

Like it or not.

Turnbull treated his audience on Lateline last night to some genuine pearls of wisdom. For instance, who would have guessed that “the virtue” of Coalition policy on climate change “from the view of Mr Abbott…is that it can be easily terminated…”

“COALITION CARBON PLAN AN EXPENSIVE CON,” Melbourne’s Herald Sun predictably screeched.

“DIRECT ACTION A SHORT-TERM FIX,” headlined The Australian.

“TURNBULL SINGES ABBOTT ON CLIMATE,” thundered The Age.

Out came the statement of support from Abbott’s office.

Malcolm Turnbull is no fool; he would have known the explosive headlines that would follow his remarks in contradicting Coalition policy so blatantly.

Not content with this success, however, today he fronted the Queensland Media Club, refusing to rule out a desire to return to the Liberal leadership. “Every member of the House of Representatives has a field marshal’s baton, or the leader’s baton, in their knapsack, so nobody can ever discount that sort of ambition completely,” he informed his audience.

Today, Turnbull’s colleagues were justifiably livid. “It was a disgrace. He’s never been a team player, he never will be a team player,” said one MP. “It’s probably frustrating for him to see Tony (Abbott) going so well. I can’t imagine he would have too much support this morning from his colleagues,” said another.

Well, quite. I guess if you were in Turnbull’s shoes, and saw the voting intention ratings Abbott is generating — enough for the Coalition to reduce Labor to 40-50 seats in the 150-seat lower house, mind — you could understand him thinking, “grab the leadership, win the election, be Prime Minister, roll out the pet projects…”

The problem is that under Turnbull — and I’ll use Newspoll from The Australian although all the polls were very, very similar — the best two-party vote the Coalition could muster was 48% (enough to lose by a fraction less than Howard did in 2007); the worst was just 41%, low enough to wipe the Coalition out for three terms.

On average under Turnbull, the two-party Coalition vote was about 43-44%. To put this in context, Paul Keating was slaughtered in 1996 with a tick over 46% of the two-party vote.

As preferred Prime Minister, Turnbull mustered 26% against Rudd’s 54% in October 2008, and 16% to Rudd’s 66% in July 2009. (Recently, Tony Abbott trailed Julia Gillard on this measure by just 3%).

As strange as it sounds today, and despite already beginning to lose control over the Labor Party in private, had Rudd gone to a double dissolution over climate change in late 2009, Turnbull would have led the Coalition to annihilation. So much for his “principled stand” on climate change. A similar stand on the same issue by Rudd killed the latter off just as it did Turnbull.

For Turnbull to return to the leadership, it would be a game-changer all right: the Gillard government would receive instant capitulation from the opposition on climate change policy, far less rigorous scrutiny of its policies, the benefit of the policy differentiation between government and opposition beginning to blur, and the emergence of a sense within the electorate that perhaps “the devil you know” is worth sticking with. Turnbull has already championed the concept of a sovereign wealth fund being established on the back of mining revenues. Just as the carbon tax would be introduced without opposition, so too would the MRRT.

Malcolm Turnbull is an impressive individual; Rhodes scholar; highly successful merchant banker and lawyer; and, frankly, quite a great guy to have conversations with. I know — once upon a time, in the early 1990s, with Malcolm heading the Australian Republican Movement and myself a precocious young monarchist, our paths crossed several times.

However, just as Turnbull has little electoral appeal, he also has form for undermining his colleagues and party policy.

Shortly after being deposed by Abbott, Turnbull couldn’t resist speaking out on climate change policy. Whilst a backbencher, my view was that he was undermining the new leader and that it had to stop — and whilst I didn’t believe for one minute I would be listened to, and that I would be dismissed outright, I nonetheless sent Turnbull a private letter on Facebook. For now, I do not propose to publish that here, but the upshot was, and I used these words: Malcolm, please, SHUT UP!

It is time for Malcolm to shut up, or go to the cross benches. The third option, a leadership challenge almost guaranteed not to succeed, would not be worth the political damage it would do to the Liberal Party just for him to try to prove the point that Malcolm is right, and that what Malcolm wants, Malcolm should have.

Analyse the polls, Turnbull. Like it or not, Tony Abbott is in tune with the mainstream majority of Australians. Just as Gillard and Labor are not, neither are you.