The U.K. prime minister, Theresa May, has inherited the situation. David Cameron, the prime minister who launched the referendum that resulted in a slight majority's voting to leave the EU, resigned not long after the final votes were tallied. May then took after and has been the focal point for negotiations since then. Several Cabinet ministers have resigned between now and then, among them Boris Johnson, who was one of the most vocal proponents of the Leave movement and who served as Foreign Minister for a time.

The U.K. government has invoked Article 50 of the EU constitution, which provides for measures to be taken in order for one country to leave the Union; it is the first time that such measures have been taken. Negotiations between the U.K. and EU have been ongoing, in fits and starts, with a March 29, 2019, deadline looming. That is the day on which the official split is to happen, as the last day of the two-year provision set for in Article 50.

The vote by Parliament is on the latest proposal put forth by May and by EU negotiators. The government is a minority one, meaning that opposition parties have more seats in the House of Commons than does May's Conservative Party. Opposition in Parliament to the proposed deal is expected to be strong.

Among the main points of contention is the trade status of the U.K. if it is no longer part of the EU. May's plan would keep the U.K. under current customs rules with regard to the EU, until new trade arrangements can be made. Such country-to-country arrangements are perennially detailed and time-consuming, and many economists fear that not enough time is left between now and the March 29 deadline to provide for such negotiations.

Another political hotspot has been in Ireland. Northern Ireland is part of the U.K. Since the advent of the EU, the border between Northern Ireland and the country of Ireland has been a "soft" one, meaning that passage between the two by people and goods is easier because both countries are part of the same organization, the EU. A consequence of Brexit is that the border between Ireland the U.K. would return to being a "hard" one. Large numbers of people cross the border from one part of Ireland to the other every day; such passages could conceivably be more problematic with a "hard" border.

Also being discussed, moreso in recent days, is the possibility of another referendum, to revisit the issue. The initial referendum was not technically binding, but May and her government have viewed it as such. In fact, Parliament earlier voted to accept the referendum results, as close as the vote was, as a message of the need for change.