On Monday, Speaker of the House of Commons John Bercow ruled that Prime Minister Theresa May cannot bring her Brexit deal back to Parliament for a third vote — at least in the deal’s current form.

Considering that the European Union has ruled out renegotiating the terms of Brexit, Bercow’s action creates a major obstacle. Up until now, May had hoped to bring her deal back for a third vote that might just have scraped over the line. But now, with Britain’s March 29 deadline for leaving the EU rapidly approaching, one of two things seems likely to happen: Either Britain will leave the EU without a deal, at the risk of significant economic hardship, or the EU will accept Parliament’s desire for an extension to the March 29 deadline.