That’s where Mrs. May finds herself now. While not quite a climate change agreement with 175 signatories, the Brexit negotiations clearly are no longer just between “London” and “Brussels.” There are multiple stakeholders, each imposing additional demands and constraints — most notably the Brexiteers within Parliament. At this point, Mrs. May has pushed the European Union as far as possible; now, like an effective mediator, she needs to figure out how to get concessions from other stakeholders.
Here is what I would advise.
First: Think through the endgame. Mrs. May and the hard-Brexit members of Parliament seem to be disagreeing over whether her deal is worth supporting, but there is a more crucial disagreement beneath the surface. If her deal is defeated, the hard-line Brexiteers prefer a “no deal” Brexit to a second referendum on Britain’s membership in the European Union. Mrs. May almost certainly prefers the latter. She will not want to drive Britain off a cliff with a no-deal Brexit.
Second: Lead and negotiate honestly. Counterintuitively, Mrs. May’s opening gambit should be to admit publicly that her deal has serious problems: She has acknowledged that her agreement is not “perfect,” but she continues to argue that the Northern Ireland “backstop” is not a real threat because no one in the European Union wants to see the backstop become a protracted reality. Unfortunately, regardless of what anyone “wants,” no one (including the prime minister) has ever explained how the Northern Ireland backstop is to be avoided or, once implemented, how it will end. The British people deserve to know this. Mrs. May would take a political hit for being honest, but it comes with strategic benefits.
Third: Convert honesty into negotiation leverage. It might not seem like a good strategy to undermine her own deal, but here’s why it works: The less people like this deal, the more likely they will be to accept a second referendum on Britain’s membership in the European Union. Polling is almost certain to show that. And when it does, Mrs. May will have further leverage with the Conservative members of Parliament who refuse to back her deal.
Fourth: Use that leverage. Mrs. May should do what she has resisted so far: announce her intention to hold a second Brexit referendum if she cannot get enough support for her deal. This is a one-two punch. First, it presents a credible threat to reluctant conservative members of Parliament who would prefer nearly anything to holding another referendum and, potentially, having Remain win. If this threat somehow fails to move enough votes, and Mrs. May’s deal is dead, the second punch follows through on the threat and lets voters vote again — having now witnessed the reality of Brexit — whether to leave or remain in the European Union. When all else fails, this helps avoid Mrs. May’s least preferred option: no deal.