Anthony Browne is former director of Policy Exchange and former Europe editor of the Times.

From local radio to national broadsheets, from Brexiteers to Remoaners, the critics of the withdrawal agreement have been as articulate as they have been passionate. There are many concerns, and I suspect the Prime Minister shares some. It has been described as “dead in the water”, because the chances of getting it through Parliament are so slim.

But even those wanting the hardest of Brexits should hold their nose, and support the agreement. They are far more likely that way to get what they want than by bringing it down. Their understandable fury at the prospect of becoming a “vassal state” is blinding them to the ugly political mood in the UK, how that will fundamentally change after Brexit – and that the agreement can be rewritten later.

If the deal is rejected, it brings the current political chaos to a new fever pitch. Uncertainty about what happens when we leave the EU is likely to be compounded by a bitter leadership battle that risks tearing the Conservative Party apart.

The political maelstrom is already causing almost palpable fear among the electorate, with plunging support for the Tories. Brexit will not be a thing of liberation and inspiration, but a byword for political vandalism.  The chaos is leading to declining support for Brexit, and increasing support for a second referendum. Some Remainers want the turmoil because they see it as the most likely way to stop Brexit. You can easily see how that can happen, starting with a request for an extension to Article 50. And if Brexit does happen, it might happen in the worst way – with both no deal and limited planning for no deal – making turmoil far more likely. Corbyn is reported to want this, as he is convinced it will destroy the Tories, lead to a general election and hand him the keys to Number 10.

But what if the deal – with all its drawbacks – is passed? What we do know for certain is that Brexit will actually happen on March 29th. We will have left the EU (at least in name), and then:

  • There will be limited economic turmoil, as most EU rules affecting trade will still apply. This will massively calm public nerves about Brexit. Project Fear will be finally killed off.
  • The campaign for a second referendum to stop Brexit will have to stop in its tracks because Brexit has happened. It will have to transmute into a campaign to rejoin the EU, which is a much more difficult and longer-term game, especially if Brexit isn’t associated with economic turmoil. I suspect it will largely dissipate.
  • Work on the positive aspects of Brexit – such as developing our own agricultural and fisheries policies – will shift public focus to the opportunities. Support for Brexit will rise.
  • The Tory Party can then in its own time decide who it wants to lead us into the next election. It can do so in a calm and considered fashion, rather than against the background of political crisis, and it can do so without being accused of recklessly bringing the country to the abyss
  • If the Party choses a new leader, and the new leader doesn’t like the withdrawal agreement, then they can ditch it.

This last part is the most important to understand. The UK would be unilaterally ripping up part of its treaty with the EU. International lawyers – the ones normally interviewed about this – absolutely hate such an idea. It risks damaging our reputation as a trustworthy country. It risks a backlash from the EU. But unique times can require unique actions. It is absolutely possible to tear up international treaties. Donald Trump is making a habit of it.

It would clearly be controversial, but it would have none of the passion of the current crisis. It would not be about something as emotive and existential as membership of the EU. I cannot see mass marches by people opposed to changes to the Withdrawal Agreement.

It is not unprecedented. The EU often shows great tolerance for its members being in flagrant breach of their treaty obligations. Sweden is obliged by treaty to join the Euro, but has refused to do so after it was rejected in a referendum. Sweden is permanently in breach of its EU treaty, and the EU hasn’t even protested. Many of the Eurozone countries, including France, have been in breach of their commitments to run balanced budgets.

The two main questions are: how could the UK ensure a stronger negotiating position; and what would the reaction of the EU be?

The UK could strengthen its negotiating position by announcing it will unilaterally disapply the parts of the Withdrawal Agreement it doesn’t like in one year’s time, giving a precise date, and then energetically and publicly plan for that, such as introducing new customs controls. The bits it might unilaterally disapply include the customs arrangement, and the payments to Brussels. At the same time, the UK could say it will immediately stop applying any new EU rules, and start enthusiastically negotiating trade deals with third countries.

The UK would have to make clear it is totally happy to walk away, and revert to WTO rules with no deal with the EU. In all negotiations, you have to establish what your walkaway position is, and then make clear you are comfortable with it you’re your negotiating strength it almost zero. There will not be public panic, because Brexit itself will already have actually happened. The debate over whether Brexit should happen or not will be over, and the national political mood will be much calmer. There could be widespread public support for insisting on a fairer agreement.

And how will the EU respond? There is actually surprisingly little they can do. Normally when countries breach its treaties, the EU threatens to fine them, as it recently has with Italy, but since we will not be in receipt of any money from Brussels they will not be able to. They could threaten to disapply other parts of the withdrawal agreement which we want, such as security co-operation, but that would also harm them, and it is certain when things have calmed down that such “win-win” co-operation arrangements will resume one way or another. They could threaten to impose trade sanctions on us, but given they export far more to us than we do to them, it would hurt them more.

EU politics may also be more helpful. Michel Barnier would be gone, Juncker will be heading for the exit, and there will be a new European Parliament with more populists and fewer federalists. A new generation of EU leaders could be sympathetic to the unfairness of insisting that a country has to accept regulation without representation, and cannot escape a treaty it doesn’t want to be in.

It won’t be easy, but it is doable. It may take two heaves to achieve a full Brexit. But that is much preferable to pushing the country to the abyss, which will jeopardise the Conservative Party, the economy and Brexit itself.