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Why Parliament's vote on the final deal is more important than its vote on triggering Article 50

The High Court has ruled that Parliament must vote to trigger Article 50

Oliver Ilott argues that it is Parliament’s role in signing off a final Brexit deal that has the greatest influence over the UK’s negotiating position and its bargaining power.

The High Court has ruled that Parliament must vote to trigger Article 50. As we continue to argue, this decision (if upheld) is likely to influence the timing of negotiations, but will not change the fact that the UK is going to leave the EU.

The more important point that people have yet to twig is that Parliament will have a vote on the final deal. Unlike the triggering Article 50 vote, this final deal vote will heavily influence the course and content of negotiations. It is central to the UK’s negotiating position and its bargaining power.

Parliament’s role in signing off the deal limits potential Brexit outcomes

Brexit negotiations will take place on two levels. On the international level, negotiators from each side will thrash out a deal. They will then take the agreed deal to the domestic level, where their respective legislators (the UK Parliament on one side and the European Parliament and member states on the other) will decide whether to sign it off. Only then does the deal come into force.

Although the ratification process comes after the negotiations, its influence is felt from the start. Neither negotiator wants to waste time notionally agreeing a deal which is then rejected by either or both legislatures. Negotiators operate with one eye on the ratification process, always trying to steer discussions towards deals which their legislature would approve.

The Prime Minister must engage Parliament throughout the process to understand what deals it would agree. In the negotiating jargon, these acceptable deals are known as the ‘win-set’.

The UK has a win-set (a set of deals Parliament will accept) and the EU has a win-set (which the European Parliament and member states will accept). A deal agreed by negotiators and then agreed by both legislatures would sit at the overlap of the two win-sets.


Brexit win-set - overlap

On the other hand, if there is no overlap between the two win-sets (no deal that could be ratified by both legislatures), then no agreement is possible.  


Brexit win-set - no overlap

To know which deals are in the frame, the Government needs to understand parliamentary preferences; what would Parliament agree, and what would it reject?

The Government needs to set out the consequences of rejection

Parliament will sign off any deal that is better than the alternative. If the deal is proposed early on in the Article 50 two-year negotiation window (which seems unlikely), and Parliament considers the deal to be bad, then the alternative is quite attractive: the deal can be rejected, and negotiations can continue.

But it seems much more likely that the deal will be proposed right at the end of the Article 50 two-year negotiation window, meaning the alternative looks very different. If no deal is signed off before the window closes (and the parties do not unanimously agree to extend this window), then the European treaties simply cease to apply to the UK overnight.

The first step for the Government in understanding which deals Parliament would vote for is to set out what this scenario would look like: what would happen to the UK’s legal relationship to European institutions, to UK citizens living on the continent and to the UK economy in the event that tariff and non-tariff barriers were erected in UK-EU trade. Once the Government knows what it would look like for no agreement to be reached, it can find out which deals MPs would prefer. This defines the UK win-set.

It is important to note that this win-set might include a large number of deals that parliamentarians consider to be harmful to the UK. But they may still find them better than the alternative (the collapse of negotiations, and the overnight cessation of European treaties). The UK win-set is not defined by what Parliament wants – it is about what MPs would actually sign off, which might be a ‘lesser of two evils’ consideration.

What deals Parliament will accept doesn’t just set the agenda for UK negotiations – it determines its bargaining power

Once the Government knows the preferences of UK parliamentarians, then it knows the size of its win-set – it knows the breadth of possible deals that Parliament would ratify. The size of the win-set size is important because it is a key determinant of negotiating power.

Smaller win-sets give negotiators far greater bargaining power. For example, pointing to a powerful legislature that will strike down all but a small number of deals, the negotiator can plausibly claim that their room for manoeuvre is extremely limited. By contrast, a negotiator with a large win-set has plenty of scope for concession.

The smaller the win-set, the stronger the negotiating hand

Historically, the EU is considered to have had a very small win-set. Its process for agreeing deals through both European Parliament and member states provides so many opportunities for a veto that there are actually very few potential agreements that it could ever hope to ratify. This is especially true for agreements that require consensus from all 27 national parliaments and 11 regional assemblies of the EU.

This means that once the EU has identified its negotiating position, it might be very hard for the UK to negotiate any changes to this – because the EU’s room for manoeuvre is limited by its ratification process. It is therefore a powerful negotiator.

On the UK side, we don’t know our negotiating power because we don’t know our win-set. But at present it seems as if Parliament would vote for a large number of deals – preferring many outcomes to the collapse of talks. These preferences may change, but if that stays the same then the UK will have a very large win-set and little bargaining power.

So Parliament’s vote on the final deal has a bigger impact on the course of UK negotiations

If the High Court decision is upheld, the next few months may focus heavily on Parliament’s vote to trigger Article 50. But this vote will only influence the timing of negotiations. However, it is Parliament’s role in signing off the final deal that will actually determine the UK’s bargaining power (or lack of it) in negotiations.

It is important Theresa May engages with MPs and Lords to understand their preferences. For the Government, engaging with Parliament is not a nicety, a concession to disgruntled MPs. It is a crucial step in understanding both the UK negotiating position and its bargaining power.

As far as possible, it is an issue that needs to answered before Article 50 is triggered, whether by the Prime Minister or by Parliament.

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