Even talking about Brexit has Britain’s Tories destroying themselves

In Tory politics, it is the mother of all cautionary tales, the fable of original sin passed from generation to generation: When the party turned angrily against itself in a brutal debate over whether Britain should continue to withdraw from the larger European and world economy. That debate ripped the party in two, set members of Parliament viciously against their prime minister and fellow MPs, and ultimately forced the PM to resign and rendered the Conservatives unable to form a majority government for almost 30 years.

That was a long time ago – 1846, precisely, when prime minister Robert Peel decided to repeal the protectionist Corn Laws, against the will of most of his party. But it felt awfully relevant this week, as Prime Minister Theresa May's effort to drag Britain out of the European Union exploded into a parliamentary self-immolation whose ferocity and divisiveness, many MPs said, have not been experienced since Sir Robert's time.

Wednesday's row, over whether MPs should have the deciding vote on Britain's eventual deal to leave the EU, revealed the fundamental, and probably irreconcilable, paradox of the Brexit project: While sold to British voters as a way to free parliamentary democracy from the clutches of Brussels bureaucracy, the only way it could successfully be passed is by ignoring parliamentary democracy.

It was Ms. May's first Brexit defeat – one delivered by a faction of rebels not from the Labour opposition or from her party's pro-European Union Remain faction, but largely from her own Brexit-supporting Leave faction. The rebels won their amendment. The sovereignty of parliament will prevail, the MPs will get the deciding vote – and that makes any viable exit from the EU all but politically impossible.

The aftermath was ugly. Stephen Hammond, one of the rebel MPs, was promptly sacked as vice-chairman of the Conservative Party. Brexit-fundamentalist MPs wanted to go further. One of them, Nadine Dorries, denounced her colleagues as treacherous and declared that "they should be deselected and never allowed to stand as a Tory MP, ever again." The battle was so vicious that the Archbishop of Canterbury stepped in and called for a "ceasefire" as it had descended into "personal attacks."

This was just a small taste of what is yet to come. For Ms. May, who spent the rest of the week in Brussels trying to negotiate a deal, the showdown exposed a fundamental and ruinous fact about Brexit: That there are two ideas of what it's supposed to be, and those two ideas are completely incompatible.

One faction, the soft Brexiteers, wants to do anything possible to keep Britain linked to the European economy. Their largest group, the "Norway/Switzerland" faction, seek a deal similar to what those countries have: Free-trade access to the European Common Market and its 500 million consumers. In exchange for this access, these countries must allow free movement of EU citizens across their borders, comply with EU laws and standards, and pay sizable annual dues to the EU – without having any influence over the EU's legislation.

The other faction, the hard Brexiteers, want a complete break from the EU, the European economy and its institutions. What the soft Brexiteers seek is exactly what they thought they were voting against.

Ms. May had been negotiating for a hard Brexit, but the Irish border has forced her into a corner. In order to maintain the support of the Northern Irish Unionists who keep her minority government aloft – and to prevent a Berlin Wall-style border from becoming necessary – she agreed to "full alignment" with EU laws and rights for EU citizens across Britain; she also agreed to substantial payments to the EU – a deal that sounds increasingly like Norway.

As she knows, the hard-Brexit faction will never view a Norway-style deal as a true Brexit. Yet her soft-Brexiteers will never allow a total break to be negotiated.

If the simple task of talking about a parliamentary vote has left her pro-Brexit MPs denouncing one another as traitors, the vote itself – given the irreconcilable visions of post-Europe life – will be destructive. A second referendum, or a victory by the even more deeply divided Labour Party, both sound more likely than a parliamentary decision on Brexit.

The only way to make Britain an island again, she has discovered, is by ignoring democracy and blowing up her party, possibly for a generation. "If we get it wrong," Tory MP George Freeman told the Financial Times this week, "I fear we'll become an isolated old people's home off the coast of Europe."