With the resignations in the past 24 hours of two of Theresa May's four most senior ministers - Boris Johnson as foreign secretary, and David Davis as Brexit secretary - something very important died.
But it is not clear whether what has been snuffed out is Theresa May's Brexit plan or Theresa May's leadership of the Conservative Party.
That at least is what Tory Brexiter MPs tell me.
Like Davis and Johnson, they see her Brexit proposal - to permanently be governed by EU rules for the making of goods and food, and also to collect EU tariffs at our borders - as a betrayal of the 17.4m people who voted to leave the EU.
And they are especially incensed by May's decision to send out her chief of staff, Gavin Barwell, to brief Labour and Scottish National Party MPs on her scheme for the UK's future commercial relationship with the EU.
They see this as an attempt by the PM to usurp them, to make common cause with the political enemy and marginalise her own colleagues.
For them this would be like Gareth Southgate bribing the Croatian team to work with Harry Kane on Wednesday, because Southgate had decided he had lost respect for his own midfield.
That is why the Brexiters are putting an ultimatum to May: drop the Chequers plan or face a damaging vote of confidence.
It's their Brexit way or the highway for May, they say.
Of course there is - to coin a phrase - an apocalyptic third way, namely the break up of the Tory Party.
We are living through history.