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Britain finally quit the European Union a week ago in a display of symbolic pomp. Union Jacks were waved, E.U. flags lowered.

Prime Minister Boris Johnson keeps trying to cloak himself in Churchillian optimism, declaring Monday that post-Brexit Britain was, among other metaphors, a butterfly “leaving its chrysalis,” flapping its way to new prominence on the world stage. He both extolled his nation’s reclamation of sovereignty from the European Union’s vast regime of rules and regulations and, at the same time, celebrated Britain’s embrace of global free trade — just days after he had withdrawn his country from the world’s most important and integrated bloc of free-trading states.

That bravura belies the wishful thinking that has coursed through the Brexit movement from its initial inception. “Leave” campaigners, including Johnson, offered rhapsodic visions of unleashed Britain’s return to worldwide primacy.

But in the weeks and months ahead, it has to reckon with some cold realities: The actual process of splitting from Europe is far from over, and Britain will probably find itself reminded, repeatedly, of its diminished standing in the world after cutting itself adrift from the continent. Moreover, the anger in Northern Ireland and Scotland over Brexit may mean that, in leaving one union, Johnson and his allies laid the groundwork for the dissolution of another.

“Brexit belongs to this era in one quintessential way,” explained New York Times columnist Roger Cohen. “It is an act of the imagination, inspired by an imaginary past, carried along by misdirected grievances, borne aloft by an imaginary future.”

Over an 11-month transition period, Johnson’s government still has to negotiate the terms of Britain’s new relationship with Brussels, including a new trade deal. These sorts of talks usually involve two camps coming together to find points of convergence, but Britain and the 27-member bloc will be settling on how their once wholly intertwined economies will diverge.

It’s a fraught process few experts believe can be substantively settled in the given time frame. European officials would like to secure a pact that keeps Britain closely in line with existing frameworks and ensures a level competitive playing field. But this week, Johnson took a hard line, saying he’d take an arrangement with Europe that involved tariffs between the two sides over a deal that leaves Britain subject to E.U. regulations and oversight from European courts. That’s in keeping with the ideological convictions of some of the pro-Brexit crowd, including members of Johnson’s cabinet who want to convert Britain into a low-tax, deregulated “Singapore on the Thames.”

The impasse spells trouble for British companies long dependent on easy access to European markets. It has also frustrated European politicians keen on an amicable accord. “We can have competition with cooperation or competition with conflict,” Ralph Brinkhaus, the parliamentary leader of Germany’s Christian Democratic Union, told the Guardian. “Listening to the government’s speeches this week, I am not quite sure what the position is of the UK.”

Johnson can’t look for much solidarity elsewhere, though. Although President Trump has been broadly supportive of Brexit, a new mega trade deal with Britain is a remote possibility in a U.S. election year and in the absence of a binding agreement with Europe. Moreover, the terms of the deal would not be particularly favorable to Britain, far and away the junior partner. Tensions have already flared between Trump and Johnson. The president was reportedly “apoplectic” in a phone call last week over the prime minister’s decision to allow Chinese tech company Huawei to have a role in Britain’s 5G mobile phone networks.

“The special relationship doesn’t mean a special deal,” Amanda Sloat of the Brookings Institution said at a Wednesday panel in Washington convened by the Council on Foreign Relations.

In a light jab at Trump this week, Johnson warned against “protectionists” in Washington. Sloat said his government’s foreign policy — be it over climate considerations or the Iran nuclear deal and other wranglings in the Middle East — is “much more closely aligned with Europe” than with Trump. At home, in part to retain the backing of former Labour Party supporters who voted for his Conservatives last year, Johnson may pursue social spending policies “much closer to where the Democrats are in the United States,” Sloat added.

For the Europeans, there’s little more to be gained from the divorce. Experts say E.U. officials are much more preoccupied with other affairs — from reckoning with the U.S.-China trade war to Italy’s potentially seismic economic wobbles to dealing with democratic backsliding in Eastern Europe. “The E.U. has bigger fish to fry,” Mujtaba Rahman, a Europe analyst at the Eurasia Group consultancy, said at the same panel. “Brexit is an annoyance that has to be managed. It’s about damage limitation.”

“I think both Europe and the U.K. are at risk of becoming weaker within the global system,” Caroline Atkinson, an official in the Obama administration, said at the panel. She suggested that the most realistic, best-case scenario would be a “fudge” over trade between the two parties.

“Most probably, Britain will enter a slow decline relative to potential,” Jeremy Cliffe of the New Statesman wrote last week. “In an emotional saga, this will be an outcome hard to get emotional about.”