(Bloomberg Opinion) — Britain will leave the EU at 11 pm London time on Friday, following Boris Johnson’s victory at last month’s general election. Much has been written, including in this column, about the results of the election, and in particular how the Labour Party lost it so badly. But Brexit also means another postmortem – why did the efforts to stop Brexit fall short?There were effectively two routes by which Brexit could have been stopped – either for parliament to legislate for a referendum with a “remain” option during last year’s standoff, or by electing a parliament that would do this. Neither succeeded.The Remainers were unable to convince enough lawmakers to back a plebiscite — on two occasions nonbinding parliamentary votes were lost narrowly. The debate will continue indefinitely as to whether and to what extent Labour’s ambiguous Brexit position hurt Labour itself. But it clearly hurt the chances of a referendum.But nor could they convince voters to elect a parliament that would deliver a referendum. This is only partly explained by the fact that many voters whose support such an effort would have needed weren’t prepared to back Jeremy Corbyn as a possible prime minister.Smaller pro-European parties could have held the balance of power after the election. Yet the reality proved to be a series of mishaps and missed opportunities, from the botched launch of The Independent Group to the ups and downs of the Liberal Democrats, the failure of the two to work together when such an alliance would have been at its most powerful, and not forgetting the vast array of new anti-Brexit “center” parties.Yet these failures speak to something more fundamental. The Remainers didn’t win the argument. It’s often overlooked that public opinion hasn’t shifted much from the 52% to 48% outcome in 2016. Number Cruncher polling indicates that Brits were still evenly divided on Brexit at the time of the election, with 46% saying it was wrong, 44% saying it was right, and about 85% of voters on both sides backing their original vote.The shift in headline numbers has been glacial and is largely explained by compositional change — those who have died since 2016 are much likelier to have been Leavers, while those newly eligible to vote are much likelier to be Remainers.Similarly, despite asking the question in many different forms, few polls showed more than narrow net support for a second referendum with an option to Remain.This paints a very different picture than the outpouring of enthusiasm for the EU shown by thousands marching and the millions signing petitions. Part of the difference is that many 2016 Remain voters — particularly fiscally conservative, “status quo” types — were quite happy to go along with David Cameron’s Remain campaign, but were never staunch Europhiles.Much like the parties, the anti-Brexit campaign groups were numerous, in some cases reflecting the intersection of Brexit and traditional party loyalties. There were certainly cases where this became an issue — for most of the general election campaign the groups couldn’t even agree on tactical voting advice.Then there were doubts around democratic legitimacy. Remainers repeatedly argued that a democracy can change its mind, as many countries indeed did after referendums on the EU that failed to ratify a significant change.However I struggle to think of a comparable referendum in which the change option had been endorsed by the public, only for voters to be asked to vote again without the change being implemented. Attempts by some activists to delegitimize the 2016 vote, whether based on allegations of campaign overspending or foreign interference, failed to move the dial.It’s also worth considering the legacy of the 2016 Remain campaign, and what lessons were and were not learned. The predictions of a year-long recession after the referendum — which never occurred — made it relatively easy to dismiss all subsequent warnings about the costs of Brexit as “project fear.”What’s more, the cultural gap underlying the Brexit divide has not gone away. While many Remainers, particularly those on the economic left, have tried to explain Brexit through economics, this was not the main driver of the Leave vote.And finally, the fatigue factor. Many people were just fed up and wanted to move on from Brexit gridlock. Boris Johnson’s mantra of “Get Brexit done” stuck and his victory provided the killer blow. But ultimately, it may well be that stopping Brexit simply wasn’t on the cards once the referendum had delivered its verdict.To contact the author of this story: Matt Singh at matt@ncpolitics.ukTo contact the editor responsible for this story: Therese Raphael at traphael4@bloomberg.netThis column does not necessarily reflect the opinion of Bloomberg LP and its owners.Matt Singh runs Number Cruncher Politics, a nonpartisan polling and elections site that predicted the 2015 U.K. election polling failure.For more articles like this, please visit us at bloomberg.com/opinionSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.