May is between a rock and a hard place over the backstop issue

If the PM fails to mollify David Davis, his resignation could spell the end of her premiershipMany will be baffled by the latest cabinet row over Brexit, pitched as the most damaging yet for Theresa May. This particular showdown, however, is significant.First, because Brexiters fear that if David Davis fails to get his way, the UK could be permanently tied to the European Union even after it formally leaves. Second, because if the Brexit secretary walks, it could bring down the prime minister.Co