How does unthinkable policy become inevitable? The ‘Overton window’ is one possible answer

Not that long ago, Australians owned many public enterprises and lived behind high tariff walls. The country ran on cheap coal-fired power. A pro-China foreign policy and a large, bipartisan migration program worked to the country’s benefit.

Today’s policy landscape would have been unimaginable to many voters 40 years ago. Most of the old state-owned enterprises now belong to shareholders. National Party leader Matt Canavan is a very lonely voice in his calls for renewed tariff protectionism.

In the face of global heating, Australia continues to experience social division over the future of its energy generation. The nation’s flagship defence policy to tackle regional uncertainty involves closer ties with old Anglosphere allies. And politicians of every hue are tying themselves in knots in a quest to lower net overseas migration.

How do policy cycles come to be, and what causes them to be remade over time? There’s a concept that could help us answer these questions: the Overton window.

What is it?

To borrow a concise definition from foreign policy expert Thomas Wright, the Overton window is the idea that there is an “acceptable range of political discourse in a society” at a given time. For example, it was once crazy-brave to argue for the end of the White Australia policy – until it wasn’t.

In democratic systems, leaders and parties tend to stick within these boundaries to remain popular and legitimate.

The concept takes its name from the late Joseph Overton, an electrical engineer and senior figure at the influential Mackinac Center for Public Policy in Michigan.

His colleague Joseph G. Lehman recently blogged that Overton’s concept was intended to “describe what think tanks do and explain why someone might support one”.

Think tanks are research and advocacy organisations. Some are staunchly independent while others are explicitly connected with or aligned to a partisan cause. An instinctive libertarian, Overton thought think tanks could stretch the limits of political possibility where risk-averse, vote-chasing politicians never could.

Overton died in 2003, with no inkling his name would be associated with one of the most widely used political terms of our times. It has become a standard phrase among policy wonks and especially in think tanks (including progressive organisations whose politics Overton would have staunchly opposed).

Shifting windows, shifting climate

The Overton window seems convenient for explaining big shifts in public policy. But just how good is it?

Could it, for example, help us understand something as messy as Australia’s embrace, and then rejection, of an emissions trading scheme (ETS)?

By 2007, the idea of an ETS to price carbon and disincentivise carbon pollution had been circulating for at least two decades. It was, according to historian Ruth Morgan, an idea that fit within the “zeitgeist of sustainable development” (as well as pro-market internationalism).

Australian governments, both Labor and Coalition, had stumbled at the hurdle of a coherent emissions reduction policy. The Howard government chose not to consider a mandatory emissions trading scheme in 2003.

Just four years later, both major parties were promising voters they would introduce an ETS if (re-)elected.

Labor, under Kevin Rudd, comfortably won the 2007 election, but failed to secure the necessary support of either the Coalition or the Greens for his ETS in the Senate. The government ultimately shelved its proposal as the public mood turned sour.

Just three years after campaigning for an ETS, Labor’s climate policy offering at the 2010 election was noticeably threadbare. There was a proposal for a citizens’ assembly, a $2,000 rebate to encourage voters to trade in older vehicles, and a promise from the new prime minister, Julia Gillard, that there would be “no carbon tax”.

The Coalition had already committed itself to opposing an ETS. As the politics got tougher, Labor moved away from its former position and toward the position of its opponents.

Governing subsequently in minority with the support of the Greens, Labor passed a modified package, including an ETS with a three-year fixed price. This proved decisively unpopular and the critics, including Opposition Leader Tony Abbott, dubbed the measure a “carbon tax” and a “broken promise” at that.

Labor suffered all the way to a devastating election defeat in 2013. Abbott’s new government repealed the ETS. George Megalogenis, in his new book Three Shocks, offers a neat account of this protracted policy drama.

Pollsters and commentators have periodically floated the idea in the intervening years, and a modest substitute exists today for high-emitting industries in the form of the safeguard mechanism.

But voter sentiment on carbon pricing remains uneven despite the best efforts of proponents and economists.

Concepts that dare not speak their names

At its most superficial, the Overton window can be deployed to explain every one of the twists and turns above. It can be made bigger or smaller, more progressive or more conservative.

The causes of change can be anything from a shocking event to a concerted campaign of advocacy, a singular act of individual political boldness or a longer, slower process of social and cultural change.

On closer inspection, there’s not much in the way of precise explanation for how change happens. The Overton window’s magic is its ability to absorb and repurpose other models of political change without ever naming or explaining them.

A concept called issue salience – how important or prominent a given issue is to voters and policymakers – matters here. Voters in 2007 were more disposed to regard climate change and emissions reduction as a serious priority for several reasons.

The Millennium Drought, the worst in Australia’s modern history to that point, made the issue of global heating and sustainability more tangible for voters. Australia’s bushfire season had commenced early the previous summer.

Action on climate had broader cultural and policy legitimacy, too. Documentaries like former US Vice President Al Gore’s An Inconvenient Truth heightened public interest, as did a major report by Nicholas Stern for the British government on the economic costs of inaction.

The “framing” of an issue – the way it’s presented and pitched to align with existing worldviews and prior beliefs – is also important.

Outside of environmental and progressive circles, the idea of action on climate change had struggled against the more pervasive concern that Australia might cause economic self-harm if it curtailed use of its abundant coal.

By 2007, commentary had reframed Australia as a global laggard in the fight to reduce emissions. There were frequent appeals to the interests of “children and grandchildren”.

Abbott proved highly effective at reframing again the entire debate, describing Rudd’s ETS as a “great big new tax on everything” and Gillard’s clean energy future package as a “tax”.

That proved fatal to Gillard’s public standing, the government and the survival of the policy itself.

As other concerns, including the global financial crisis, came to the fore, climate change slipped down the list of issues for most voters. According to the Australian Election Study, climate change was “extremely important” in the federal vote decision for 52% of voters in 2007, but that figure was down to 30% in 2010.

There is a whole family of concepts in political science that try to explain how politicians respond to this type of change in voter sentiment. Among these concepts are convergence theory, rational choice theory, median voter theory and catch-all political parties.

These very different theories reach for a common set of conclusions. They hold that voters will follow their own perceived economic interests, and political candidates will converge on a position that causes the least offence to the greatest number.

Each of those concepts, in some way, sheds light on aspects of the rise and fall of the Emissions Trading Scheme policy in Australia – even if we are sometimes not our most “rational” selves at the ballot box.

The limits of boldness

The Overton window draws its appeal from the idea that impactful think tanks, landmark reports and leading advocates are the real change agents. The rise of the concept closely tracked the rapid proliferation of think tanks from 1990 onwards.

Such actors played a role in the national policy changes I referred to at the outset. And they’ve been major characters in the ETS story, too.

In his memoir, John Howard described Gore’s documentary and the Stern report as elements of a “perfect storm” that forced him into offering an Emissions Trading Scheme.

Journalist Marian Wilkinson shows in her book Carbon Club that when the tide ran against carbon pricing, there were business-backed right-wing think tanks leading the charge, including new outfits in the United Kingdom alongside older ones, such as the Institute of Public Affairs.

Individual politicians often make a difference. Many of Abbott’s opponents have credited him with singlehandedly killing off a generation’s hopes for a climate policy built around an ETS. In his memoir, Rudd calls Abbott a “giant wrecking ball” of “singular, destructive impact” on the nation.

But these are the judgements of the defeated and the frustrated – and they contradict the Overton idea that change comes from outside the political elites.

There is some room in the Overton model for social movements and rank-and-file party memberships, but not a lot. That’s perhaps not surprising, as there are ever-fewer members to exert real pressure on parliamentary leaders.

But they do still make their mark sometimes. This was true of Liberal members and their advocacy against an ETS in 2009.

Media space and political opportunity are central to the Overton concept. Yet one doesn’t need a copy of The Communist Manifesto in their lap to appreciate that larger social and economic forces shape political change. Those forces are slower to materialise and harder to evaluate, but that makes them all the more important.

The Overton window is not the only tool, and certainly not always the best, for that work.

Dr Joshua Black is a lecturer in Australian political studies within the Vice-Chancellor’s Centre of Public Ideas at the University of Canberra.

He has previously been a Postdoctoral Research Fellow at The Australia Institute, Palace Letters Fellow at the Whitlam Institute within Western Sydney University and a ministerial speechwriter. He is the author of Performance Politics: Australian politicians and the stories they tell (NewSouth 2026) and co-editor, with Frank Bongiorno and Carolyn Holbrook, of Gold Standard? Remembering the Hawke Government (NewSouth 2026).

This article is republished from The Conversation under a Creative Commons license. Read the original article.