I frequently hear the same thing at Westminster, regardless of whether or not the person in question voted to leave the European Union or not: that, after March 2019, Brexit will be “over”.
It’s true that on 30 March 2019, the United Kingdom will leave the EU whether the government has reached a deal with the EU27 on its future relationship or not. But as a political issue, Brexit will never be over, regardless of whether it is seen as a success or a failure.
You don’t need to have a crystal ball to know this, you just need to have read a history book, or, failing that, paid any attention to current affairs. The Democratic primaries and presidential election of 2016 hinged, at least in part, on the consequences of the North American Free Trade Association (Nafta). Hillary Clinton defeated a primary opponent, Bernie Sanders, who opposed the deal, and lost to Donald Trump, who also opposed the measure.
Negotiations on Nafta began in 1990 and the agreement was fully ratified by 1993. Economists generally agree that it has, overall, benefited the nations that participate in it. Yet it was still contentious enough to move at least some votes in a presidential election 26 years later.
Even if Brexit turns out to be a tremendous success, which feels like a bold call at this point, not everyone will experience it as one. (A good example of this is the collapse in the value of the pound after Britain’s Leave vote. It has been great news for manufacturers, domestic tourist destinations and businesses who sell to the European Union. It has been bad news for domestic households and businesses who buy from the European Union.)
Bluntly, even a successful Brexit is going to create some losers and an unsuccessful one will create many more. The arguments over it, and the political fissure it creates, will not end on 30 March 2019 or anything like it.