Frances Lenoir / Reuters

LONDON—Just before lunchtime on October 17, 2019, Britain and the European Union announced a deal on a smooth British exit from the EU. This is the second such deal in less than a year. The previous deal was rejected by Parliament and capsized the career of former Prime Minister Theresa May. Will this new deal come to a happier conclusion? And what is happiness in this context anyway?

The new agreement is reportedly 500 pages long, recapitulating most of the elements of the rejected 2018 agreement. There is, again reportedly, one big difference between May’s deal and Prime Minister Boris Johnson’s: Ireland. (The word reportedly is doing a lot of work here, because I write only a few minutes after the agreement was announced and before the release of the full text.)

Ireland! Always Ireland. For nearly 150 years, disputes over Ireland have broken British governments, wrecked British parties, and sparked guerrilla war and terrorism on the two islands. The issue seemed to have been settled forever by the Good Friday Agreement of 1998. Brexit revived the Irish issue, in all its ancient intractability.

The core of the problem is this: Once the United Kingdom quits the EU, there will be a border between the U.K. and the EU. That’s the point of the whole exercise after all, to insert a border. No border, no Brexit.

But where should the border be placed? “Britain” is an island, but the United Kingdom of Great Britain and Northern Ireland straddles two islands, creating a land border between the U.K. and the EU. That land border runs jaggedly around the northeastern quadrant of Ireland. Northern Ireland is only about 180 kilometers from water to water, but the winding Irish boundary bobbles up and down and around for 500 kilometers—longer than the entire French-German border!

Reinserting the border between the two Irelands will not only impose a terrible economic burden, but also endanger the hard-won peace on the island of Ireland. The Good Friday Agreement created an economic and human unity among Irish people, ending three decades of terrorist violence. Few wish to return to the old divisions, to checkpoints and armed guards—and to the risk of armed attack on those checkpoints and guards.

During the 2016 referendum, Johnson and other eminent Leavers promised that the border could be enforced unobtrusively. There would be no checkpoints, no targets for terrorists. New technology would collect taxes and prevent smuggling in a way lawful travelers and businesspeople would never notice.

That concept sounded suspiciously too good to be true to the EU negotiators. They demanded a so-called backstop: All right, United Kingdom, go ahead with your magic technology! But until it’s up and working, both islands—Ireland and Britain—will remain inside the EU’s trade and tariff border.

It was this backstop that wrecked the May government.

But if the border is not carved across Ireland—or drawn around both Ireland and Britain together—then there remains only one other place it can plausibly go: down the Irish Sea between Ireland and Britain. And this is what Johnson appears to have agreed to today.

A lot of rhetoric is being expended to obscure this concession, but this is what seems to have been conceded. And what a concession it is!

Since the 1880s, a crucial part of the identity of the Conservative Party of Great Britain has been the defense of the union between Britain and as much of Ireland as wished to remain attached to Britain. For this cause, Britain fought a war against the Irish Republican Army from 1919 to 1921, then endured a terrorist campaign by a revived IRA after 1969. Over 30 years, 3,500 people lost their lives in the Irish Troubles, including more than 1,000 British soldiers and police. The Good Friday Agreement preserved Northern Ireland as a constituent element of the United Kingdom, a decisive victory of the union cause.

The reported EU-U.K. deal continues the political union between Britain and Northern Ireland, but it apparently severs the economic union. Northern Ireland will have one customs and value-added-tax regime; Britain another. If Britain enters into, say, a free-trade agreement with the United States, Northern Ireland apparently will not. Over time, under this agreement as reported, Northern Ireland will be subsumed into ever closer union with the Irish Republic and the European Union.

This economic merger must have political consequences. In 2016, Northern Ireland cast 55 percent of its votes for the Remain side in the EU referendum. The threat to the Good Friday Agreement seems to have pushed Northern Irish opinion even further away from Britain. One of the most reliable measures of British public opinion, the polls commissioned by the Conservative peer Michael Ashcroft, finds that a plurality of Northern Irish people, 46 percent, would now vote to quit the U.K. and unify with the republic to their south. (Northern Ireland used to have a substantial Protestant majority, but higher Catholic birth rates and the migration of young Protestants to the British mainland have equalized the two main religious groups in the province.)

Meanwhile, the Brexit process has radicalized English opinion against the Irish, northern as well as southern. Among Conservative Party supporters, 59 percent would prefer to let Northern Ireland go rather than compromise on Brexit.

Johnson is heeding his party members with this apparent deal. But he is also heading toward a future in which the United Kingdom itself becomes a casualty of the Brexit process. Scotland is even more pro-EU than Northern Ireland, and Conservative Party members are even more willing (63 percent) to sacrifice the union with Scotland to the Brexit cause.

Getting from here to there may be difficult. By a law adopted in September, any EU-U.K. deal must be approved by the British Parliament—where Johnson has never commanded a majority. The votes of Northern Irish members of Parliament will be indispensable to Johnson. Johnson is offering them enormous sums for economic development in return for their support—but the whole reason for being of the Northern Irish party in the House of Commons is the British union, and agreeing to be merged economically into the EU may be unacceptable to its members at any price.

If the Johnson deal fails in the vote expected Saturday, then the Brexit process gets extended to January, and Britain probably heads to a new election that Johnson could easily lose.

The issue in that election becomes radically stark: Brexit or union? The English nationalism that powers Brexit is repelling the rest of the United Kingdom. It’s not Brexit. It’s Engxit—and Engxit not only from the European Union, but Engxit from Britain, too.

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