I F ANYONE DESERVES a prize for stamina, it is Theresa May. The prime minister spent the run-up to Christmas defending her Brexit deal before MP s, who still show no sign of voting for it. She had hoped the EU summit on December 13th and 14th would agree to sweeten the deal to make it easier for MP s to swallow, particularly regarding the Irish “backstop” that may keep Britain in a customs union. But EU leaders refused. They said they hoped not to use the temporary backstop, but rejected a time limit or a unilateral British right of exit.

Mrs May still hopes to win something from Brussels that helps her to get the deal through Parliament. She cites earlier changes for countries that have had problems ratifying treaties, from Belgium and the Netherlands to Ireland and Denmark. But there are big differences with Brexit. It is more palatable for the EU to make concessions to a member than to a non-member. It is easier to find changes that help to reverse a narrow referendum result, as in those countries, than to overturn a big negative parliamentary vote of the sort Britain is heading for. And in past cases the process has taken months or years, whereas Brexit is due in March.

All this means the parliamentary vote on the deal, planned for mid-January, looks sure to be lost. What then? Mrs May’s strategy seems to be to run down the clock. The March 29th deadline will be closer, and with it the risk of a no-deal exit. Yet although time pressure could change a few Tory minds, she will need Labour votes to get her deal approved. And with Labour leaders pressing for an early election instead, she is unlikely to secure them.

This is leading MP s and even some in the government to ponder alternatives. Some ministers suggest a series of indicative votes in Parliament to test whether other forms of Brexit—the close Norwegian model, or a looser Canadian-style arrangement—might win greater support. But none of these is likely to command a majority. Anyway, the response in Brussels will be that only Mrs May’s version of Brexit, negotiated over almost two years, is on the table and ready to be ratified.

This explains growing talk of a second referendum. Mrs May says this would do irreparable damage to British politics. But Mujtaba Rahman of the Eurasia Group, a consultancy, puts its odds at 40%. It is now, in effect, the most popular backstop.