How fares the average Brexiteer, with less than a week standing between Britain’s independence from the European Union? Euphoric? Or exhausted? Probably a little of both. Anxious, too, if truth be told. For while there is agreement among both Leavers and Remainers that the UK will exit the EU on January 31, what happens after is very much up in the air.

Britain’s choice to leave was grounded on its desire to regain those vital elements of sovereignty that EU membership requires to be shared with the Brussels bureaucracy. Border controls, tax and regulatory policy, trading frameworks, and legislative oversight were areas in which jurisdiction — and sovereignty — was no longer absolute. Brexiteers, meanwhile, were emphatic they wanted to take back control.

Exiting the EU at the end of January is only first step. The UK will then enter a “transition period” as it negotiates a future trading relationship with the EU-27. Prime Minister Boris Johnson promises to sign a free trade agreement by the end of year. He claims that since there is already complementarity of trade rules between the EU and the recently “departed” UK, charting the course forward ought not to be cumbersome. His EU counterparts are neither so sanguine nor so accommodating.

Fleet Street reports that the European Commission is considering curtailing any agreement to accept British goods on a “common standards” basis. Its broad aim, as European Commission president Ursula von der Leyen admitted, is to coerce Britain into aligning its trading interests with the EU on a “level playing field.” As French minister Amelie de Montchalin confessed, their goal is to stop Britain becoming “a tax haven at the gates of Europe.”

Can there be any doubt that Brussels is less interested in concluding a trade agreement with its former UK colleague than in sending a warning to prospective seceding states? Forfeiting EU-member status won’t be easy and won’t be cheap, is the menacing message. We will tie you up for months in excruciating and likely futile discussions. We will protect our own prerogatives at the expense of easing the path for seceding states.

If there was any doubt that this is the EU mandate, the record since Britons voted in the 2016 referendum to leave puts paid to any reservations. Nothing compares in the annals of British history to the perfidy of MPs, civil servants, and vested interests of the “chattering” classes that Britain’s exit would be controversial and messy. Other countries — France and Ireland in previous EU dealings — were foolhardy to buck the wishes of Brussels and eventually buckled under the pressure from within and without. Only Britain has had the fortitude to advance so far.

To his credit, Mr. Johnson has told his Cabinet to go “hell for leather” in pursuit of an American trade deal, prioritizing negotiating with the U.S. over the EU. Such action signals to Brussels that Britain is tired of being toyed with; its demands for “alignment” are undoubtedly a provocation. Such a concession puts in doubt Britain’s viability to conclude global trade deals. So the prime minister is resolute: Either the EU stands down and treats the UK as it would any other country in negotiating a deal or Britain steps away and seeks bilateral agreements elsewhere. Time will tell if the leverage will dislodge intransigence from Brussels.

President Trump, for one, is unquestionably on “Team Boris.” “We look forward to negotiating a tremendous new deal with the United Kingdom,” the president reiterated this week from the World Economic Forum at Davos. “They have a wonderful new prime minister,” he said and, venturing into the realm of understatement, Mr. Trump said of Mr. Johnson, “He wants very much to make a deal, as they say.”

Allusions between Britons’ struggle for independence from the European Union and their heroic victory at the end of World War II are obviously fatuous; comparison tortures credulity. Still, the desire for freedom frames each historic event.

So it is not unreasonable to recall Sir Winston Churchill’s reminder to the British people in 1945, which has lost none of its poignancy in 2020. “Our pilgrimage has brought us to a sublime moment in the history of the world. From the least to the greatest, all must strive to be worthy of these supreme opportunities,” Churchill counseled against complacency. “There is not an hour to be wasted; there is not a day to be lost.”

Stephen MacLean, a freelancer based in Nova Scotia, writes the Brexit Diary for the New York Sun.