Prime minister Theresa May will formally announce her wish to quit the European Union, and thus trigger separation proceedings under Article 50 of the 1991 Maastricht Treaty, on 29 March.
Current Labour Party policy is to give the Tories a free hand to shape Brexit. Labour leaders say they must defer out of respect for the referendum decision on 23 June 2016.
Labour leaders have talked about "holding the Tories to account" and pushing a "People's Brexit", but surrendered the means to make those words reality by voting with the Tories when they legislated to give themselves a free hand.
The Tories explicitly rejected amendments requiring regular reports to Parliament, or allowing Parliament to vote down a "final" deal and force renegotiation.
Shadow Chancellor John McDonnell said last October: "The Government is hurtling towards a chaotic Brexit that will damage our economy, and hurt the poorest and most vulnerable most of all.
"By pulling up the drawbridge and tearing up longstanding ties to Europe, we will inflict huge and unnecessary pain on our society. Yet a hard-line Tory minority believe [in] the fantasy of turning our whole country into a giant offshore tax haven, with rock-bottom wages and no public services. It is a nightmare vision that I believe would be rejected by the majority of people who live here".
Labour should be convincing people, including those who voted for Brexit last 23 June, that this Tory Brexit should be rejected by the majority, and that the majority should have the means to block it.
Plebiscitary democracy - decision by one-off vote, with terms of the vote decided by the government, and the implementation which determines what the one-off vote really means also decided by the government - is a thin form of democracy.
Lively democracy means the continual formation, revision, and re-formation of a majority opinion, with minorities always having the chance to become majorities. Labour's deferential attitude means letting live democracy be killed by dead quarter-democratic forms.
The referendum result gave a new right-wing leadership in the Tory party a boost for their agenda. Labour has to accept that as a fact. It doesn't have to, and shouldn't, "accept" any moral obligation to cease opposing that agenda.
The Tories are shaping Brexit in a right-wing way. In our view, that goes with the terrain, but it was not clear to the voters on 23 June, nor something that the majority voted for then.
Since January, Theresa May has repeated that "no deal is better than a bad deal", meaning that the Tories retain the option - to be used by them at will, whatever Parliament thinks - to go for quitting the EU on terms that would leave British citizens in EU countries, and EU nationals in Britain, stranded; that would block travel and movement between Britain and the EU; that would disrupt trade and supply chains by tariffs and heavy border paperwork; that would erect "hard" borders between North and South in Ireland and, quite possibly, between England and Scotland.
On 15 March Brexit minister David Davis said: “We wanted to be clear we could actually manage this [a no-deal exit] in such a way as to be better than a bad deal and that is true... It's not as frightening frankly as some people think".
So he has found "clear" facts? Not at all. "I can't quantify it for you in detail yet. I may well be able to do so in about a year's time".
What if the Tories get what they think a "good deal"? Even that will be bad.
They insist on quitting the EU Single Market, which allows trade to flow across borders without tariffs or delays, although polls have shown 90% in favour of staying in. They want to withdraw, in large part, from the looser Customs Union, which even Turkey is in.
They want, above all, to stop free movement and cut immigration, from non-EU countries as well as from the EU. Making Britain a walled-off, meaner country will hurt working-class unity between workers of different countries and origins, and impoverish it economically. Since immigrant workers pay in so much in taxes, and disproportionately staff public services, the walling-off will create great pressures for further social cuts.
So far the Tories are circumspect about trashing workers' and other rights which entered British law from the EU. But they say openly that they will use so-called "Henry VIII powers", allowing the government to change laws without reference to Parliament.
Labour's deference on Brexit also undermines the work of rebuilding Labour support.
The Labour right wing's staged Shadow Cabinet resignations in June-July started the process which has given Theresa May a lead in the polls despite unpopular policies (continued benefit cuts, new schools cuts, grammar schools...) But the new line of deferring to a supposedly fixed Brexit majority has worsened it.
While the Lib-Dems - despite their so-recent record in government, despite the fact that one-third of their voters went for Brexit on 23 June, despite everything - have doubled their membership by making at least some show of fighting the Tories' Brexit, Labour's surge in membership has been paused or even slightly reversed.
We cannot beat the Tories by deferring to them. Labour should fight Brexit all the way!