It’s just 11 days until Britain is due to leave the European Union and it’s still entirely unclear how or if that will happen. In the latest twist Monday, the speaker of the House of Commons delivered a serious blow to Theresa May by saying the prime minister might not be allowed to call a third vote on the deal she hammered out with the EU. May’s deal has been resoundingly rejected by lawmakers twice—once in January and again last week. After last week’s defeat, the government said it planned to organize a third vote in a last-ditch attempt to have it approved before the March 29 Brexit deadline. However, Speaker John Bercow ruled Monday, citing an obscure precedent set in the year 1604, that May is not permitted to call a vote on something that is “substantially the same” as a proposal that has already been rejected by the House. With no prospect of re-opening negotiations with the EU, it’s unclear how May can now persuade the speaker that the proposal for the third vote would be substantially different. If so, May’s deal is effectively dead and leaves two routes—crashing out of the bloc with no deal on March 29, or persuading all 27 other EU member states to approve a long extension to that deadline to allow time to work out an alternative. A May government spokesperson said Bercow gave it no warning that he was about to take that step.