The crunch point in the Brexit debate is in late 2018 to early 2019. That's when Article 50 talks end without a deal, with a bad one or with politically explosive transitional arrangements. That's when the effect of currency devaluation will be felt in people's pockets and manufacturing firms might start upping sticks to Europe if they think tariffs and non-tariff barriers are about to hit. That's the weak spot in the Brexit plan.
Brexit is unlikely to be stopped. The chances are that it'll go through and we'll be out the EU in March 2019. But there are a variety of ways it could be reversed or softened. Perhaps the Commons would vote against the deal Theresa May brings back from Brussels. Perhaps she will instead die of a thousand cuts, her authority stripped away by countless smaller defeats in the Commons on treaties or aspects of the great repeal bill.
That's why all the real debate now is about putting in place advantageous democratic structures for 18-months' time. The Lords will vote this afternoon on what happens if MPs reject that final deal. Does it mean the UK falls out of the EU onto WTO rules, with no transitional arrangements in place? This is the cliff edge, an act of national hara-kiri which would cost probably hundreds of thousands of jobs and Britain's international reputation. Downing Street demands this is the only option because they know no sane person would choose it. It therefore follows that whatever deal she brings back, MPs will back it. The Lords amendment alternative is to demand the approval of parliament before the deal is concluded and also the approval of any decision to leave the EU without an agreement. It will probably pass, with the support of a few Tory rebels in the Lords.
May's plan is to stand firm. She has told the Lords that the amendment would "incentivise" the EU to be tough in negotiations. Actually, as Lord Kerr told the Lords a few days ago, democratic accountability at home helps rather than hinders negotiations. The Americans in particular are adept at telling partners 'I hear you, but Congress would never accept it'. This won’t affect May's position. She doesn't really care about negotiation dynamics except in so far as she can reduce any obstacles to her autonomy in pursuing them.
This morning there were also attempts to bolster May's position on the second front – the death from a thousand Commons votes. Writing in the Telegraph, William Hague advised that she repeal the Fixed Term Parliaments Act to neutralise this disadvantage.
Hague believes that May has a nuclear option when these votes start: she can call an election. After all, Labour under Jeremy Corbyn look set to go down to perhaps just over a hundred seats and May currently enjoys a healthy poll rating.
Except she can't go to the country because of the Act, which demands she either pass a vote of no-confidence in her government and give the opposition time to put together an alternative, or get two-thirds of the Commons to back another election. Labour MPs are unlikely to back that option because they know they are heading for the abyss. So May would be stuck: unable to get crucial votes through, but unable to trigger an election. A lame duck, trapped in the gears of a crucial historical moment.
Hague is right to be worried. Despite their silent obedience over Brexit, there are signs of life in the only opposition that really matters: the Tory benches. Conservative MP Heidi Allen has introduced an amendment on child refugees which has the backing of moderates in her own party like Anna Soubry and Nicky Morgan. Senior ministers have written to Tory MPs to stave off a rebellion on business rates. An amendment to the children and social care bill tabled by MPs David Burrowes and Maria Miller succeeded in making sex and relationship education compulsory last week. It's perfectly possible Tory moderates will eventually throw a spanner in the works of Theresa May's grammar school plans. That tiny majority suddenly looks really quite vulnerable to friendly fire.
If you are critical of the government's approach to Brexit this is undoubtedly a good thing, but Brexit supporters who have maintained their sense of national responsibility will greet it positively too. The country has no functioning opposition. The great repeal bill hands ministers incredible powers, through statutory instruments, over nearly half a century of law. There is a real and present danger of over-mighty government, driven by a supportive press, at a moment of acute political change.
Into that vacuum have come three oppositions: the currency, which is making its own views clear about government policy, Europe, which will do so shortly, and now, hopefully, Tory moderates, who appear to be slowly finding their voice.
Some of these oppositions may appear disastrous. The currency, for instance, will hammer British living standards. But the message they are delivering might help prevent actions which would be even more catastrophic. Many in the currency markets believe that the prospect of falling onto WTO rules – if it becomes real rather than a threat - could trigger another catastrophic decline in the value of sterling.
As those repercussions become more and more real, opposition will become more and more widespread, both in the country and in parliament. That's why May's supporters and hard Brexit ideologues are trying to limit the forms of accountability and democratic control which can be wielded in 2019, both through a take-it-or-leave-it Commons vote and a repeal of the Fixed Term Parliament Act.
Hague is right when he says that "real trouble is coming" in 2019. The decisions taken now will help define how many safeguards the British people enjoy from its worst effects.
Ian Dunt is the editor of Politics.co.uk. His book - Brexit: What The Hell Happens Now? - is available now from Canbury Press.
The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.