The most important thing that happened in Australian politics on Monday was that a prime minister conceded he could not pass legislation through the House of Representatives.
"We propose bills in the House when we believe we can carry them and so at the moment we don't have, because it is a one-seat majority and that's a fact of life, we don't have enough support to do that," Malcolm Turnbull told reporters.
It was an abject moment. Turnbull was admitting that he had lost control of his government. Later in the day, in question time, he made plain that it was because of the lack of support in the Coalition, not because Labor was opposed.
Turnbull was on the brink of clinching agreement on carbon emissions policy when he was opposition leader in 2009, but Tony Abbott tore him down at the last moment before he could seal the deal with the Rudd government.
Turnbull was on the brink again last week, and again this week, but once again Abbott has frustrated him. It's an Abbott-led revolt that has killed Turnbull's proposed National Energy Guarantee.
If the bill were to go to the House, Abbott would have only a handful of Coalition members with him in crossing the floor, perhaps three to five, but that's more than enough.
Turnbull's supporters are angry and frustrated at Abbott. But among many in the conservative faction of the Liberal Party, there is glee. Turnbull has been humiliated. And, to the conservatives' great satisfaction, he has been humiliated over what they consider his pet fetish - climate change and carbon emissions.
"Turnbull is obsessed with this issue," says a leading conservative MP. He thinks it's a "'greatest moral challenge of our time' type of initiative", a reference to the Kevin Rudd description of climate change. It was a challenge that Rudd failed because of an internal insurrection and now Turnbull has been forced to abandon too.
Contemptuously, he adds: "Turnbull thinks people will fall on their knees and say hallelujah! We're back to the innovation message", Turnbull's campaign theme that fell flat at the 2016 election and which he has since abandoned. "He's blind to the politics because he's obsessed with the issue."
But the defeat is about much more than climate change. It's an ideological and identity marker. And it has exposed Turnbull's jugular. "You can't have a government," says a Dutton advocate, "that can't rely on the House on a key piece of legislation."
The majority of the conservatives have got what they wanted by destroying any move to regulate carbon emissions, but it's not enough. They are setting out to destroy Turnbull's prime ministership and replace him with one of their own, Peter Dutton. And to date they are in the ascendant.
But Labor says it supports the NEG, and it certainly supports cutting carbon emissions. Why doesn't Turnbull reach across the aisle, negotiate with Labor and bring the NEG bill to the House?
Because, while the bill would doubtless pass, it would bring on a Coalition revolt on the floor of the House. "Our people just would not tolerate being photographed sitting with Tanya Plibersek and Bill Shorten to vote on a bill," says a conservative Liberal.
Knowing the bill would pass in any case, many Coalition backbenchers would feel free of any of the constraints of loyalty to the Prime Minister and exercise loyalty to their ideological position. They would cross the floor in force to oppose their own government. Conservatives estimate that perhaps 20 or more would vote to oppose Turnbull, putting him in an untenable position.
The fact is that he's in an untenable position anyway. The Fairfax-Ipsos poll published on Monday shows a brutal collapse in the Coalition primary vote of 6 percentage points in the space of a month, down to 33 per cent.
On a two-party basis, that puts Labor into a commanding lead of 55 per cent to the government's 45. In an election, those numbers would wipe out 21 government MPs. That is landslide stuff and terrifies many Coalition members.
"A lot of our people are facing that fact that they are in the last six months of their political careers," says one worried backbencher. "They've got houses, school bills, cars that they've set up for themselves on the basis that they're earning $200,000 plus. What do they do if they're suddenly out of work?"
The Fairfax-Ipsos poll also makes a clear assignment of responsibility. Turnbull's approval rating was down by 9 per centage points. His standing as preferred prime minister was down by the same margin.
This may be unfair. It's Abbott and other conservatives who have revolted against Turnbull, yet Turnbull is being judged responsible. Disunity is death - Abbott delivers the disunity, Turnbull gets the death. But that's politics.
The poll doesn't just expose a dramatic fall in support for the government. It feeds the conservatives' narrative in favour of Dutton in a specific way. Of the 6 per cent of voters who've abandoned the government, only 1 per cent seem to have switched to Labor and another 1 to the Greens.
Meaning? "The votes aren't going to Labor, aren't going to the left," says a Dutton supporter, "because it's our base, they're walking away from us. It's a devastating blow."
And while the poll cannot definitely supply the answer, it does suggest that this is at least partly true. The poll detail shows that the biggest primary vote swing against the government was outside capital cities where support fell by 8 per cent and among people aged over 55, also down 8 per cent. These groups are more likely to be part of the Coalition conservative base.
So if the problem is the loss of the Coalition's conservative base, the answer must be the leading conservative cabinet minister and leadership contender, Dutton, as his advocates are arguing.
Can Dutton actually win an election for the Coalition? That seems implausible. The only member of the government with a polling-proven ability to lift the government's vote is Julie Bishop.
That brings us to the other three important things that happened on Monday. First, Julie Bishop, resisting entreaties from moderate colleagues, decided that she will not stand for the leadership so long as Turnbull remains prime minister. That clears the way for Dutton.
Second, Dutton's resolve to challenge Turnbull for the leadership hardened and his advocates said that his support in the party room had firmed. They claim a majority, which is hotly disputed by Turnbull's people.
And third, Dutton's plans were hit with the trauma of a Channel Ten story reporting that he is in violation of the constitution's section 44 (v) through his wife's business interests. Dutton says he has legal advice that it's a non-issue. Sydney University constitutional law professor Anne Twomey says it's a "borderline" case that will probably need to be decided by the High Court.
This is a problem for Dutton and may delay or derail his bid. But either way, it's not enough to save Turnbull. It would take a miracle to defeat the momentum of conservative anger from within and public disenchantment without.
Peter Hartcher is political editor.
Peter Hartcher is the political editor and international editor of The Sydney Morning Herald. He is a Gold Walkley award winner, a former foreign correspondent in Tokyo and Washington, and a visiting fellow at the Lowy Institute for International Policy.