We can’t be sure precisely when Australia’s major political parties lost the public on the issue of offshore detention, but the morning of August 20 confirmed it.

It was day one of a planned three-month Kids Off Nauru campaign, initiated by World Vision, and it began with Rupert Murdoch’s conservative tabloid newspapers firmly on the bandwagon.

That morning, Sydney’s Daily Telegraph ran a heartwarming picture of a young child, born into detention on Nauru, on its front page.

Inside, across two pages, there were more pictures, along with an emotive account of the lives of the “stateless babies” and the other “unseen children” living in mouldy tents, sharing dirty bathrooms, playing with donated toys on the “rocky remnants of a phosphate mine and staring through the wire fences of the camp”.

The same piece ran on the front of the Adelaide Advertiser and, inside, in Melbourne’s Herald Sun and Brisbane’s Courier-Mail.

This was a big development, though not so much because it indicated the Murdoch empire was setting out to shift public opinion on the indefinite detention of children. The piece amounted to an acknowledgment that public opinion already had decisively shifted.

As a Murdoch newspaper source told The Saturday Paper this week: “Whatever else you might say about News Corp, we can see which way the wind is blowing.”

In the months before that story ran, the source said, editorial decision-makers at News Corp had divined that popular opinion was rapidly shifting on offshore detention, and that they should start shifting with it – for business as much as for humanitarian reasons. Like political parties, populist media is poll-driven.

And so, when World Vision came to them, offering an on-their-own story about the children on Nauru, News Corp ran with it.

The story carried an “exclusive” tag and the byline of Jennifer Sexton, who was handpicked by Ruth Lamperd, news editor at World Vision, because she was “a good, straight reporter”. Lamperd and her team had done a lot of legwork to pull the story together, calling in favours from its network of contacts developed over the past five years on Nauru.

World Vision had been planning for that day – the launch of the Kids Off Nauru campaign – for two months. Pictures and video of the kids on Nauru were taken “by a person who won’t be named and can’t be known”. They organised for the families of the children to give their informed consent for the use of the images. They provided the quotes from the families about the kids’ mental and physical health concerns.

“Australians like order. We don’t like queue jumpers, we want the queue to proceed in an orderly fashion. The queue should be quick and children should not be trampled in the queue.”

And they dropped it to The Daily Telegraph, specifically, because it is a populist publication with a conservative readership who may not be reached by other media that’s been covering Nauru closely over the past few years.

“The offshore issue has been dealt with in a very comprehensive way by various serious media,” Lamperd says, “but it becomes a bit of a circle, where the people who are reading about it are the people who already care about it.”

The reasoning behind giving the exclusive to The Telegraph was not just that it would bring the issue to a different audience, but that it would send to the government – and also to the Opposition – a clear message. If even the right-wing press were on board with the move to get children off Nauru, the situation had become politically untenable.

The campaign exerted pressure in other strategic ways, too. On September 20, for example, the Christian humanitarian organisation Micah sent a delegation of women leaders to Canberra to lobby. They represented a range of faiths – Anglican, Baptist, Salvation Army – and most notably several representatives of big Pentecostal churches. They met with various politicians of professed faith, from both major parties, and had a 40-minute meeting with Home Affairs Minister Peter Dutton, the public face of the government’s hardline asylum seeker policy.

Again, the significance was not just in the message, but in the people delivering it – religious conservatives, the kind of people the Liberal Party’s religious right is wont to describe as “the base”.

It took a few months for the reality to sink in with the politicians. Then, this week, the Morrison government capitulated to the Kids Off Nauru campaign. On Thursday morning, Simon Benson of The Australian came with the exclusive announcement: “The Morrison government plans to have all children of asylum-seekers still on Nauru relocated to Australia by the end of the year.”

On the face of it, things seem to have moved very quickly. In some ways, they have. Several hundred organisations – not just the usual refugee activist groups but a large number of churches and even an array of corporate entities – signed up to the Kids Off Nauru campaign almost immediately. According to refugee advocates, there were 119 children on Nauru on August 20, when the campaign started. It is understood that 135 people, including 47 children, have come to Australia since October 15 – many on medical grounds, and almost always after legal action. The Australian reported that only 40 children remained.

It’s a testament to the impact of The Telegraph’s coverage that the Kids campaign, which had been planned to run for three months up to Universal Children’s Day on November 20, was able to achieve its goal three weeks early.

According to the organisers, though, the removal of children from offshore detention is just its first step. As the campaign’s website says: “Our position is that no-one should be held indefinitely and an enduring solution must be found for everyone.”

The Reverend Tim Costello, chief advocate for World Vision and chief executive of Micah, says the key to the Kids Off Nauru campaign lay in the separation of two related problems – the issue of how Australia secures its borders against a further influx of asylum seekers and the other issue of how we deal with those who have come, and been detained, already.

“The first thing we had to do was simplify the message,” he says. “But the problem was, the refugee activist community was split between pragmatism and principle.”

Principle holds that boat turnbacks are just as are wrong in law as indefinite offshore detention.

As a policy brief by the Kaldor Centre for International Refugee Law summarised last year, the military-led border security operations of Australia – and those more recently adopted by European nations – do not accord with the United Nations Convention on the Law of the Sea, the Convention on Maritime Search and Rescue, the Safety of Life at Sea Convention, the Refugee Convention or the core international human rights treaties.

Unfortunately for principle, though, the turnback policy remains popular with the public.

“That,” says Costello, “is why people like Robert Manne, John Menadue, Frank Brennan and I started arguing and writing pieces saying that whatever we think about the turnback policy, it needs to be unhinged from offshore detention.”

Costello freely concedes that some refugee advocates believe them to have “sold out” because their argument is essentially based on the premise that boat turnbacks have been so successful that Australia can afford to lighten up on detention. The continuation of interdiction is the price of freeing the people on Nauru and Manus.

However, various polls attest to the reality that public opinion now endorses this utilitarian view. Only last weekend, a YouGov Galaxy poll published in The Sunday Telegraph showed almost 80 per cent of people wanted children and their families transferred off Nauru. Again, it ran on page one. This time the headline was “Free Nauru Kids: Voters tell PM to take NZ offer.”

The Wentworth byelection was another clue to the big shift in popular opinion, with the treatment of asylum seekers identified alongside climate change and the dumping of Malcolm Turnbull as a major issue for voters.

Kerryn Phelps, who took the seat, ran hard on the issue of kids in detention. She is still running hard on it. “The suffering of those people held in offshore detention, particularly children, is something the Australian people don’t want any longer to have on their conscience,” she tells The Saturday Paper.

“People know the realities now: one in four children suicidal, children with traumatic withdrawal syndrome. I believe it has become personal. People start to see their own children, their own grandchildren, in these kids. It was, ‘No, not in our name.’ ”

Phelps campaigned on bringing them to Australia. But she did not oppose boat turnbacks.

“I believe we want strong border protection policies, but you can have them without having offshore detention,” she says.

“Certainly, if we have offshore processing, that should be rapid and have a quick resolution.”

It is an astute position, as social researcher Rebecca Huntley can attest. There is good evidence to suggest the Australian public now shares the view that the time has come to get everyone out of offshore detention.

By coincidence, at the same time as the Kids Off Nauru campaign launched, Huntley was working with a series of focus groups in Peter Dutton’s electorate of Dickson, north of Brisbane.

The five groups she spoke with were carefully selected to include people who had voted for Dutton at the last election and were considering either not voting for him at the upcoming election or were undecided. The overall message she got from the groups was that “it was looking grim for him. Really grim.”

That’s hardly a major revelation, given the general unpopularity of the government and the 1.8 per cent margin by which Dutton holds Dickson.

More interesting was what the groups told her about asylum seekers. It underlined the tactical cleverness of the Kids Off Nauru campaign and also suggested even the government’s new promise to get the children off may not be enough.

“Those undecided voters were 100 per cent behind boat turnbacks, but really did not like offshore detention at all,” Huntley says.

“They and other groups I’ve worked with don’t see turnbacks as an interlocking policy with offshore detention. Their view is, if you’re turning back boats effectively, you don’t need detention. And they knew that most people were getting here by plane anyway.

“And it’s a larger thing than just the kids. There is a sense that the system is not working. They called it a failed experiment. They want an orderly and certain process that doesn’t involve the detention, particularly, of children. But not only of children.”

Huntley’s conversations revealed that these voters – swinging Liberals – were concerned about the government’s secrecy, about the perception that it had no longer term plan, and about the fact the situation had become generally “disorderly”.

“Australians like order. We don’t like queue jumpers, we want the queue to proceed in an orderly fashion. The queue should be quick and children should not be trampled in the queue,” she says.

Then there was the matter of cost. These people resented the fact that every case, every request for the medical transfer of a physically or mentally damaged detainee, was expensively fought in the courts. They also disliked that detention saw money flowing to corrupt governments.

It’s hard to argue with their perception about cost. The offshore detention regime is ridiculously expensive, as the Kaldor Centre showed in a fact sheet released in August, citing official audit figures. It costs $400,000 a year to hold an asylum seeker in offshore detention, compared with $239,000 to hold one in onshore detention. It costs about $40,000 for an asylum seeker to live in the community on a bridging visa while their claim is processed.

The official line of the Home Affairs bureaucracy, rigidly adhered to by the major political parties, is that if they were to allow those asylum seekers to come here, it would create a powerful “pull factor”. More boats would come, more people would die at sea. No doubt the view is sincerely held by many who remember the number of boat people that preceded the decision to implement offshore detention, and who worry that a fickle public has forgotten.

Earlier this week – indeed, on the day before the government’s announcement that it would bring all the children to Australia – the head of the Home Affairs Department, Mike Pezzullo, was asked by The Saturday Paper for his view on why public sentiment had shifted on offshore detention. He replied simply: “Amnesia.”

When asked to elaborate, he repeated “amnesia” and recalled that “when the boats were coming, and people were drowning, the imperative was ‘Stop the boats’. Absolutely, the imperative was ‘Stop the boats’…”

The next aim of the Kids campaign, according to Tim Costello, is to resolve Morrison’s issue with resettlement to New Zealand. During the Howard government’s offshore detention regime, 401 refugees were resettled there – without the prohibitions Morrison is demanding on future entry to Australia.

“New Zealand is the good Samaritan in this parable,” says Costello. “And Australia is like the priest and the Levite, not prepared to help. In fact, we’re beating up on the good Samaritan.”

Late on Thursday, Dutton denied the children were being removed from Nauru out of humanitarian concern. Instead, he emphasised the $1 billion yearly cost of offshore detention.

He insisted none of the hundreds brought to Australia would be allowed to settle permanently, yet continued to spurn the New Zealand offer for being a pull factor.

If Rebecca Huntley’s focus group research reinforces the view that it is no longer politically useful to hold people in offshore detention, it is nonetheless clear the asylum seekers remain hostage to politics.