Given the political roller-coaster ride the cause of British independence has endured for most of 2019, these several weeks of politicking before Thursday’s general election have been anticlimactic. Like most electoral campaigns, parties vie to outdo one another with promises of bounty. Conservative or Labor — with minor parties joining in — merely prepare the final bill to future taxpayers. The one difference, of course, is the fate of Brexit.

Prime Minister Johnson criss-crosses the country to the mantra “Get Brexit Done.” His leading challenger, Laborite Jeremy Corbyn, vows to renegotiate Mr. Johnson’s agreement with the European Union and then, remarkably, campaign in a second referendum to remain. Other party heads are pledged either to such a referendum “do-over” or cancelling the Article 50 exit outright. With only a handful of seats at stake for them, they have little to lose; they gamble that more outrageous platforms will stand out.

The one outlier is Nigel Farage and his Brexit Party. Kudos to Mr. Farage for making during the 1990s the UK Independence Party the pre-eminent voice for British sovereignty. That culminated in a Conservative premier, David Cameron, calling for a referendum in 2016 to placate Eurosceptic Tories. When Mr. Cameron’s successor, Theresa May, failed to deliver the referendum decision to leave the EU earlier this year, Mr. Farage formed the Brexit Party.

After the party’s singular success in the European parliamentary elections in the spring and amid anti-Brexit mayhem in Parliament — principally to the charge that Mr. Johnson’s deal is little better than Mrs. May’s agreement — Mr. Farage vowed to take his party to the polls for a “clean break Brexit.”

At first, the Brexit Party aimed to field candidates in all 650 constituencies. When fears mounted that, by challenging Conservative incumbents, Mr. Farage risked giving Remainers control of the House of Commons, he reversed himself and conceded Tory safe seats.

Yet even this strategy came under fire this weekend, when a number of leading Brexit MEPs criticized this concession as a continuing risk, by weakening Conservative challengers to Labor seats. They argued this reversed a previous commitment of contesting only constituencies where Tories were demonstrably weaker than Brexit Party candidates. Instead these Brexit MEPs urged electors to forsake Mr. Farage, marshal the independence movement behind one party, and vote Conservative.

The reasons are two-fold. As the December 12 election date nears, Britons opposed to Brexit are signalling they will vote strategically against the Tories. Thus, early polling that predicted Mr. Johnson would enjoy an 80-seat majority in the Commons have now been halved. The Prime Minister’s own consultant, Dominic Cummings, warns Conservatives against complacency in the face of Brexit hostility.

Tactical thinking on the ultimate fate of Boris Johnson’s deal is another reason for the regrouping amongst Brexiteers. For while the Conservative party has closed ranks around its leader, many proponents of British independence are doubtful whether Boris’s deal is all he claims.

Still — and thanks in large part to pressure applied by Nigel Farage in the early days of the election campaign — the Prime Minister has promised to conclude trade negotiations that will sever EU regulatory oversight by the end of 2020, forestalling fears of another long slog of UK-EU bargaining. Failing agreement, the Tories are prepared to leave according to WTO rules, resurrecting hopes for a clean break from the European Union. (Even now, Conservatives have not ruled out a “no deal” Brexit in relation to finalizing their deal on January 31.)

All is for nought, however, if the Tories fail come Thursday to win a majority government. “Battered and bruised as we are,” Leavers contend to the weary, “this is not the time for Brexiteers to falter and lose the battle for British independence.” With four days to go, it is “once more unto the breach” for Brexit.