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.