Malcolm Turnbull might not enjoy lowering himself to the depths of his predecessors, but ignoring the big juicy policy target Bill Shorten has given him would have been political negligence, writes Peter Brent.

The Malcolm Turnbull of 2015, the Prime Minister who consciously treats voters as adults, speaking to us honestly and intelligently, has collided with political reality.

Some are complaining that he is morphing into Tony Abbott, but really he's just behaving like an Australian politician, in an election year, faced with narrowing opinion polls.

Perhaps he believed he could remain above the fray and leave the dirty work to others. But with Treasurer Scott Morrison appearing to have hit his level of incompetency, and Finance Minister Mathias Cormann's rhetorical skills just so-so (and in the other chamber), there's only so much ranting Christopher Pyne can manage. And that other attack dog, reliably ferocious for 17 years, Tony Abbott, is now a bookish backbencher.

A microcosm of Turnbull's conflicting aspirations could be observed over the space of a few days last week in his evolving response to the Opposition's announcement that it would make changes to capital gains tax and negative gearing.

His initial reaction on the Monday was quite low key: this is a poor idea for such and such reasons, he condescended, Labor obviously hasn't thought this through, nice try, boys and girls, but back to the drawing board.

Perhaps someone then got into Malcolm's ear and explained that it's in for a penny, in for a pound in this game; he's an Australian major party leader and he jolly well needs to start behaving like one. By week's end he was thundering about the diabolical carnage the policies would wreak on ordinary, hard-working Australian mums and dads, smashing the values of their homes. His government is still at it this week.

Every prime minister and treasurer, in my memory at least (back to the early 1980s), would have done the same, particularly in an election year, even if deep down they saw merit in the policy.

The ALP has chosen to hoist a big juicy target and present the Coalition with at least five and a half months to pick and hack at it before the election. For the Government to neglect that opportunity would have amounted to political negligence.

With most Australian voters owning (with or without the bank) a dwelling, and swinging voters overrepresented by young families with mortgages, the message that a Labor government will see assets drop in value is a powerful one, especially when entwined with lingering perceptions of their economic incompetence from (again, perceptions of) their time in government.

Labor's plan might objectively be exactly what is needed to address housing affordability. It may get a tick from most experts. That doesn't make it politically wise.

And the initial thumbs up from voters in opinion polls will be a distant memory by the time of the election. There are so many potential losers, albeit by small dollar amounts, and the distinction between lowering house values, and lessening the amount by which they increase, will be lost.

Ask Labor how they feel about their housing policy during the campaign when it's getting in the way of their core message: let's throw this rotten government out.

The rather desperate retort from some Labor supporters, that the prospect of lower housing costs will prove a net electoral plus, is a pipe-dream. Home-hunters are a minority of voters, and even if they weren't, the prospect of having to pay slightly less for a home in the future is easily trumped by that of diminishing value of something you already own.

An alarming sickness has recently gripped the political class: the idea that elections are the place to unveil good policy. For a while it appeared both parties this year had succumbed to this opinion page-generated fantasy, but now one side, the Coalition, seems to have come to its senses.

It's closer to the truth to suggest that addressing the high cost of housing is too important a task to take to an election, where it will likely be trashed and linger as a lesson in what not to do.

It's something best done mid-term, having not been mentioned, or even outright denied, at the previous election. Like nearly every other important policy change you can think of, the GST being an obvious exception.

All re-elected federal governments survive in part, or largely, by warning of Armageddon if the opposition gets into office. You may not think much of us, they explain, but the alternative is much worse. Fear of the unknown and untried is a powerful political tool.

Oppositions achieve office when electors are of a mind to throw out the government, and find the alternative acceptable. Parties who lose sight of this basic dynamic get themselves in a tangle. Recall federal Labor in 2004, after caucus had taken at face value voters' declarations that they yearned for muscularity and conviction in an opposition leader.

Bill Shorten is falling for the same trick; he's into "standing for things", in large part to arrest the drift to the Greens. That's fine, in small doses. Bill is not the innately frightening figure Mark Latham was. Wednesday's impromptu calling out of Cory Bernardi worked just fine.

Differentiation from the incumbent is smart too, within reason. Taking a big economic policy to the ballot box is not.

Turnbull, meanwhile, doesn't appear to enjoy lowering himself to the depths of his predecessors. This isn't why he entered politics. Perhaps one day he will find a balance between that which people liked about him - his being the grown-up in the room - and the demands of the political contest. He will regain some of the old dignity.

But that'll have to wait until after the 2016 election.

Peter Brent is a writer and adjunct fellow at Swinburne University. Visit his website and follow him on Twitter @mumbletwits.