Allies of Theresa May have long talked about how she wants her legacy to be about more than Brexit. But the brutal truth is that there is no such legacy available to her. Rather, her choice is between being the Prime Minister who got a withdrawal agreement through or the one who had to ask for a long, humiliating extension. If May wants to increase the chances of the former being her legacy and not the latter, then she is going to have to promise to go at some point before the next meaningful vote.
Earlier today, one office holder in the ERG told me that if May said she would leave once the Withdrawal Agreement Bill was through the number of Brexiteer rebels would reduce to 20 or so. But it is not just on the ERG side that the prospect of a new prime minister would help. Nine Tory MPs voted against the deal last week for non-Brexiteer reasons. At least a third of this group would shift if the deal passing would result in May going.
One can argue about whether MPs should change their votes based on whether May goes or not. But there’s no doubt that it would have an impact. No one can be certain whether it would result in the deal passing, but it would certainly make it more likely. Indeed, if a promise to go helped the deal over the line, May would be able to claim that she had delivered both an orderly withdrawal from the EU and prevented a split in the Tory party. But if May won’t say this and the meaningful vote fails again, her legacy will be a long extension to Article 50 that would embarrass the country, be detrimental to the national interest and could end up rendering asunder the Tory party.