Scott Morrison was keen on the idea as a way of appealing to the religious and social conservatives in the Liberal base, but most ministers were wary. A ban would open a can of worms. As Julie Bishop had earlier told reporters when asked about the US Congress' rule prohibiting sex between politicians and their staff: "We wouldn't want to cross the line, so moral police were able to dictate what happens between consenting adults," she said, reflecting majority Coalition opinion. Loading But Turnbull decided to act regardless. He gave Joyce no warning of the press conference, no heads-up on the ban, and no hint of the harsh judgment he was about to pronounce. In the maximum possible media glare, Turnbull said: "The real issue is the terrible hurt and humiliation that Barnaby by his conduct, has visited on his wife, Natalie and their daughters and indeed, his new partner. Barnaby made a shocking error of judgement in having an affair with a young woman working in his office. In doing so, he has set off a world of woe for those women and appalled all of us."

The Prime Minister was announcing a ban on sexual relationships between ministers and their staff members to make sure that such a thing would never happen again, he said. He had encouraged Joyce to take leave. "He has to consider his own position, obviously." A reporter asked Turnbull: "Why would you not urge Barnaby Joyce to resign now?" This was the key political question. If it was so grave a misjudgment, why hadn't Turnbull demanded Joyce's resignation already? Turnbull answered that it was a matter for Joyce to reflect on. In fact, Turnbull knew full well in advance that there was no chance of Joyce resigning. How did he know? He had not asked Joyce if he had considered resigning, according to informed sources. He had not suggested that he consider resigning.

However, he had taken some indirect soundings through ministerial colleagues, informed people said. Those soundings told him that Joyce had not the least intention of considering his position. None. Now, two days later, the Nationals leader told Turnbull not to air his concerns about his personal life in public again. And Turnbull accepted this point without demur. So before and after his public denunciation of Joyce, the Prime Minister knew that Joyce was not going anywhere. Turnbull told reporters on Sunday: "Now the important thing is Barnaby and I are working closely together as we always have, he’s obviously taking leave coming this week and we look forward to him returning from that at the end of the week." So much for taking leave to consider his position. In his private exchange with Joyce on Saturday, Turnbull defended his right to be concerned about his personal conduct. The story had rocked the government and dominated the media.

Joyce agreed. But, he said, Turnbull had chosen timing and volume that were over the top. It had looked like he was vilifying Joyce. In future, Turnbull should put his concerns in private. So what was all the prime ministerial fuss about? Turnbull knew that his public shaming of Joyce would not force him out. In fact, Joyce considers the story to be a passing event that he likened to food poisoning.

"It's like asking people when they've had food poisoning from fish whether they'd eat fish again. They always say no. "But within a month or so you're sitting down having barramundi with them," he tells Fairfax Media. Prime Minister Malcolm Turnbull announces his ban on ministers having sexual relationships with their staff. Credit:Alex Ellinghausen Joyce thinks that the tide on the matter has already turned. Faced with a Newspoll on Monday showing that 65 per cent of respondents thought he should resign as Nationals leader or retire from Parliament altogether, he says that support in his electorate is strong and that the people of New England can see through the media storm: "Once people get a sense that they're just sticking the slipper into someone, opinions change. And they change in favour of the person getting stuck into. It's no longer reporting, it's malice. For a while it's interesting and salacious, now they are saying 'they're just trying to get stuck into you'." His electorate and the people in the regions know that he has delivered for them: "I have never stood in the pulpit or the podium as a saint. I stand on my record."

So fish sales are down. But Joyce seems robustly confident that they'll bounce back. Joyce answers to his own party and his own electorate. The leader of the Nationals is deputy prime minister automatically under the Coalition agreement because it suits both parties, with their separate constituencies, to pool their numbers. Without the Nationals, the Liberals would be out of power. And without the Liberals, the Nationals would never get their hands on the national Treasury again. Talk of a "divorce" is bizarrely ill-informed. Turnbull is powerless to move against Joyce. He knew it then and he knows it now. His public assault was performance art. It was designed to impress religious and social conservatives with his high standards, and younger voters and women were supposed to admire him for correcting the power imbalance between male bosses and their female employees. But Joyce was never going to budge. "My life has been a huge fight. This is just another one," he says.

A working relationship with Turnbull endures. Indeed, in between Joyce's slap back at Turnbull on Friday and their Saturday meeting in Sydney, the pair spoke to each other by phone at least three times, on the Joyce affair but also on matters of government business. There will be a new wariness between the men, but Joyce has no fear of Turnbull. The last big public split between them was over carbon emissions. Joyce went on to become deputy prime minister. And Turnbull was the one who went to the backbench. Fish anyone? Peter Hartcher is political editor.