LONDON — Many Americans think of Britain and England as synonymous. That’s not so, and today’s election in the United Kingdom can only be understood if one sees the nation accurately: It is a collection of countries and political tribes.

The U.K. includes four distinct nations. England is by far the largest in terms of territory and population and has always dominated the others. Wales has been been ruled from London since 1283, but the Welsh language and Welsh nationalism continue to flourish in some parts. Scotland only became formally part of the U.K. in 1707 and remains linguistically and culturally distinct. Finally, Northern Ireland consists of the six northern counties of Ireland, which remained part of the U.K. after the rest of Ireland became independent in 1922.

Each nation has its own separate party structure arising out of different political questions. The dominant question in Northern Ireland is whether the nation should remain part of the U.K. or rejoin Ireland. “Republicans” favor Irish unity while “Unionists” favor the current structure. This division falls largely on religious lines, with Catholics being Republicans and Protestants being Unionists. England’s main parties won’t even contest the election here, with the battle instead taking place between two Republican parties (Sinn Fein and the Social Democratic and Labour Party), two Unionist parties (the Democratic Unionist Party and the Ulster Unionist Party), and a small fifth party, the Alliance Party, that attempts to transcend the divide.

Scotland’s politics are driven by the question of Scottish independence. The Scottish National Party has become dominant since the failed Scottish independence referendum in 2014 and is running on an anti-Brexit, pro-independence platform. The Conservative Party is officially the Conservative and Unionist Party, and hence has emerged as the party that attracts Scots opposed to independence regardless of feelings on Brexit. Labour once dominated Scottish politics because of the working-class vote in places such as Glasgow, Dundee and Aberdeen, but has now sunk to a poor third place in Scottish polls. As a result, Labour’s leader, Jeremy Corbyn, can only become prime minister if he strikes a deal with the SNP, and its leader, Nicola Sturgeon, says the price of that deal will be another Scottish independence referendum.

These nationalist disputes are not troubling England or Wales much, although the latter has its own small nationalist party, Plaid Cymru, which will likely win three or four of Wales’ 40 seats. That’s in part because Brexit is not insignificantly a measure of English nationalism itself. Lord Michael Ashcroft, a billionaire and the proprietor of the influential Conservative Home website, conducts his own extensive polling operation and found in 2016 that people who considered themselves English rather than British were much likelier to back Brexit. Earlier this year, he found that a majority of English Brexiteers would rather leave the European Union than keep Scotland and Northern Ireland in the U.K. if it were not possible to do both. The red and white flag of Saint George, not the Union Jack, is increasingly the flag of choice outside of London.

English politics is tribal in a way American politics haven’t been since the decline of post-Civil War voting patterns. Labour voters are historically driven by antagonism toward what they view as an aloof, arrogant ruling class. A middle-aged man from the marginal seat of Peterborough, summed it up nicely: “You’re born into Labour,” he told me as we walked to a soccer match together. My cab driver last night is a Labour-backing resident of Enfield and was quite emphatic: “I will never turn my back on the party that has always fought for the people and brought in most of the benefits we enjoy today, over the opposition of the Conservatives,” he intoned. Labour’s chances tonight depend on working-class voters who want to leave the E.U. deciding at the last minute that they will vote their tribe over their preferences.

Tories have historically been their own tribe based on social class. Much of the past 15 years of British politics has been driven by former prime minister David Cameron’s efforts to reunite the tribe after his predecessor, Tony Blair, and the Liberal Democrats seduced many upper- and middle-income voters to abandon the Tories. But to attract those voters, Cameron had to move the party so far to the center that the party effectively split, with traditional conservatives backing Nigel Farage’s UK Independence Party and then his Brexit Party in this year’s European Parliament election. Conservatives are trying to woo the Cameron wing back by focusing on Corbyn and his spending plans, but polls show the Tory vote will likely comprise more voters from the lower social classes for the first time in modern history.

Prime Minister Boris Johnson’s stock line is “get Brexit done, unify the nation, and unlock Britain’s potential.” With two of the four nations opposed to Brexit, and the English tribes finally splintering over it, that is easier said than done.

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