What's Next for the U.K. If Parliament Shoots Down the Brexit Deal?

Another critical vote on the Brexit deal is fast approaching. On Dec. 11, the British House of Commons will vote on the agreement that the United Kingdom and the European Union reached in mid-November. According to the deal, the British exit from the union on March 29 will be followed by a 21-month transition period, during which the United Kingdom will remain in the EU single market. If the United Kingdom and the European Union fail to find a way to keep the border between Northern Ireland and the Republic of Ireland open by the end of the transition, the United Kingdom will stay in a customs arrangement with the European Union until they can find a solution as part of a provision known as the Irish backstop. Effectively, the deal stipulates that the United Kingdom cannot unilaterally withdraw from the customs arrangement....