Every so often I meet people who are much more knowledgeable than I am about the terms of our departure from Brexit:  who have actually read the detailed terms, as I haven’t, and regard it as the best available, if complicated, and potentially deeply undesirable, terms of departure, which have been secured as the result of lengthy negotiation with Brussels.   The question then is as to whether or not the House of Commons will accept the terms as agreed in their vote on December 11th.   The answer is, probably, but not inevitably, not.   The current arithmetic suggests that the vote will be lost by somewhere between 20 and 50 votes.   Then what happens ?   The vote could be put to the country on a three-way vote between remaining in Europe, accepting the deal as currently proposed, and crashing out (pure Brexit).   If the vote on the current deal is lost, Mrs. May would probably have to resign unless she agreed to put the vote to the country.   If she resigned, who would take over ?  Who knows ?