For Brexiteers apoplectic at perpetual deferment of Britain’s exit from the European Union, I must be the bearer of sad tidings. Like Prometheus, their gut-wrenching agonies are without end. A snap election on December 12 will exacerbate their turmoil. UK independence from the EU is as elusive as ever.

Prometheus, according to Greek myth, was punished by Zeus for having given humanity the gift of fire. His fate was to be tethered to a rocky crag where each day, to excruciating pain, an eagle tore out his liver. At night the organ regenerated, and Prometheus’s torments were renewed with the rising sun.

Much as each day Parliament inflicts fresh insults to the cause of British independence. The Prime Minister’s agreement with Brussels is only the most recent assault upon the patience of the British people. Prime Minister Johnson returned from negotiations beaming, superficially succeeding where his predecessor, Theresa May, had failed, by reopening talks and removing the reviled Irish backstop. On inspection it’s only been moved to the Irish Sea, a variant of border disorder.

Mr. Johnson’s plan perpetuates Britain’s subservience on such questions as trade, migration, fisheries, and the ongoing oversight of the European Court of Justice. For the pleasure of divorcing the EU, ante up £39 billion — a cost that could double as concocting a long-term agreement may require 3 years to hammer out. If this initial handiwork is an indication of the Government’s negotiating acumen, the future bodes increasingly ill.

True to form, MPs punted on Boris’s deal. Owing to what is known as the “surrender act,” this required the Government asking Brussels for an extension. The Prime Minister sent a counter-letter, politely asking the EU to ignore the first.

Then the Speaker of the House ruled that convention prevented a subsequent examination of the deal — a welcome diversion for the Commons. It turned its focus upon enabling legislation, gave it preliminary approval for “public consumption,” but quibbled with the Government’s timetable for speedy resolution.

Brexit then entered a state of “limbo” in parliamentary parlance, its fate in the hands of EU bureaucrats increasingly exasperated by Remainer supplication. Brussels, strapped for cash and facing an economic downturn, made all the appropriate tut-tutting remonstrances but in the end agreed to prolong Britain’s agony until the end of January 2020.

This is the third such extension since the original March 29 deadline: a provisional April 12 deadline and the now moot October 31.

This Promethean purgatory also plagues the minority Conservative government. Several times it tried to force a general election to break the deadlock, and each time failed, most recently on Monday — unable to meet the required two-thirds majority mandated by the Fixed-term Parliaments Act.

Yet a legislated end run around the fixed-term act — arguably not cricket, by Brits’ standards, since a simple majority suffices for passage — amazingly got through the Commons Tuesday by a vote of 438 to 20. Why the marked reversal in voting numbers? The Fates are fickle. Next stop, in any event, the House of Lords.

Two obvious Remainer amendments were rejected by the deputy speaker: Giving the vote to callow 16-year-olds and EU nationals resident in the UK, inane proposals from the opposition to throw an election in favor of the EU.

Curiously, Labor leader Jeremy Corbyn gave his consent on the basis that “no deal” is off the table. True, thankfully, only insofar as no Brexit business will transact with Brussels until a new Parliament is formed. (Despondent Brexiteers make poor playthings for the Fates.)

Herein Brexiteers are most akin to the fated Prometheus. Tories, through exhaustion, perhaps conviction, and more likely a mixture of pride and pique to “save face,” will stand by Mr. Johnson’s bad deal. This is fatal. The Government is blind to the futility of negotiating with Brussels.

By clinging to a failing strategy, the Conservatives are alienating their one ally in the cause of British self-government, Nigel Farage and his Brexit Party. Polling shows that they are more popular than Tories in Labor-leaning, Leave-voting constituencies. Yet Mr. Johnson has ruled out any electoral pact to win Brexit.

For his part, Mr. Farage is amenable to cooperation but will not align his troops to push “Brino” down the throats of the British electorate. Only through a “clean break” Brexit is independence viable, he realizes; any other option is “Brexit in name only.”

And there’s the shame of it. Three years after the exit referendum, the United Kingdom remains in thrall to the European Union. Two Tory governments have produced agreements that do nothing to bring about real independence. Parliament is stuffed with Remainers who never wanted Brexit and are determined to frustrate it at whatever cost to British prestige, institutional integrity, and democracy itself.

Were a clean break Brexit to survive an election campaign, hope is reborn. Just maybe, Messrs. Johnson and Farage can form a “Leave Alliance” and rally the nation. If not, Remainers will take the rein, running roughshod over dispirited and disgruntled Brexiteers. The chances of another Conservative minority government, or a socialist ministry led by Mr. Corbyn, loom like a nightmare such as only Prometheus could conceive.

As for the Greek Titan, he was eventually freed from his torments and bondage by Hercules. But without a politician with the Herculean skills to accomplish Brexit, British independence is likely to suffer a fate similar to Prometheus, bound indefinitely to the European Union.