(Bloomberg) -- With just a week to go until Theresa May has to put her Brexit deal to Parliament for a make-or-break vote, U.K. negotiators are reaching into obscure international treaty law to find a fix for the most toxic part of the divorce.
May is sending Attorney General Geoffrey Cox back to Brussels on Tuesday to try to negotiate legally binding changes to the so-called Irish backstop. If he succeeds then May’s deal has a chance of getting through Parliament next week, allowing for an orderly divorce. If he fails, Britain tumbles into unprecedented political uncertainty -- with Brexit probably delayed.
While the bloc is reluctant to make concessions, European officials want May’s deal to get through Parliament before March 29 -- the day Britain is scheduled to leave. A delay would be messy for both sides, and the EU is divided as to how long any extension should be. That could just play in May’s favor.
U.K. negotiators are looking at whether the Vienna Convention on the law of treaties, an agreement dating back to 1969, could provide an escape route, according to two EU officials. The convention sets out when governments can walk away from prior commitments.
The EU isn’t convinced, and instead is pushing for a solution based on arbitration. It’s prepared to add detail to the existing deal on how either side can demand arbitration if future talks fail to find a replacement to the backstop.
The backstop, the most contentious part of the divorce agreement, keeps the U.K. in a customs union with the EU “unless or until” a future trade deal or other arrangements make checks on the border unnecessary. May needs to win over pro-Brexit members of her Conservative party who consider the backstop an unacceptable surrender of the U.K.’s future autonomy.
Talks between the two sides are focusing on helping Cox change his legal opinion of the backstop arrangement. In legal advice in December, Cox expressed concerns about the existing wording. If he changes his mind, the idea -- perhaps optimistic -- is that pro-Brexit lawmakers fall into line.
