Call it summer EU-phoria.

There was a blazing sun overhead as European leaders arrived in Brussels for their summer summit Thursday, and the political outlook seemed just as bright, with an array of crises in check, economic indicators on the upswing across the Continent, and spirits lifted by a series of ballot-box triumphs.

Perhaps most importantly, the leaders arrived to tackle an agenda packed with issues that showed them not only unbowed by Brexit but even capitalizing on the U.K.'s impending departure to push forward in areas such as defense cooperation where London had long thrown up obstacles.

Summing up the optimism, Council President Donald Tusk said: "This is the 80th European Council in which I have participated as prime minister or European Council president, but never before have I had such a strong belief that things are going in a better direction."

"Our optimism should still be extremely cautious," Tusk said, giving a brief disclaimer, seemingly intended to ward off any jinx.

"But," he continued, "we have good reasons to talk about it. Among them are: economic growth in each and every country of the EU; falling unemployment with the highest level of employed people ever recorded; the financial agreement with Greece; the surge of pro-European sentiment in recent weeks according to the polls; the election defeats of anti-European parties and victories of political leaders who stand 100 percent for the EU, from Bulgaria and Austria to the Netherlands and of course France."

In other circumstances it might seem like so much self-inflated political spin. But in truth, the bloc, which was buffeted for years by the eurozone and migration crises and the nadir of the Brexit vote, has undergone a remarkable turnabout in fortunes.

The election of the centrist and pro-European integrationist Emmanuel Macron as president of France has sent hopes soaring of a renewed Franco-German power nexus at the heart of the EU. And Macron's colleagues seemed intent on making sure that his European Council debut was a successful one, in part by allowing him to push a strong message on the need to protect against unfair trade practices.

"That's the story: Europe is back. We’re back in business" — A senior Council official

After a first series of meetings on Thursday afternoon, German Chancellor Angela Merkel confirmed that the mood behind the scenes was uncharacteristically upbeat.

While other recent summits had focused on "critical developments," Merkel said the atmosphere was noticeably brighter and the summit was an example of how Europe could move forward. "Today the emphasis was on optimism," she said.

The summit was not only a showcase for the new French leader.

Commission President Jean-Claude Juncker, the bloc's éminence grise, also used the gathering to continue pushing the conversation about the EU's future that he successfully jumpstarted with a well-received white paper earlier this year.

Indeed, Juncker hailed the leaders' swift approval of a historic plan for greater military cooperation as the culmination of decades of work and he expressed personal satisfaction that the initiative known as "permanent structured cooperation" was finally being implemented after existing on paper for a decade as an unused provision of the Treaty of Lisbon.

"I said this is the sleeping princess of the Lisbon Treaty," Juncker declared at an afternoon news conference with Tusk. "Well, the princess is now awakening."

With few signs of discord, leaders planned to issue a meaty, 12-page set of conclusions on Friday that would show them taking proactive steps on every salient issue of the moment including defense, security and counterterrorism, climate change, jobs and economic growth, trade, migration, digital innovation, and cybersecurity.

To be sure there were potential trouble spots, notably sharp differences among EU nations over how and where to relocate two agencies — the European Medicines Agency and the European Banking Authority — from London after Brexit. Predictably, many countries are vying for those prizes.

Even that potentially treacherous discussion appeared to have been navigated successfully, at least for the moment, with leaders agreeing on a process that would delay the decision for about a month, until November, but would avert a clash by setting a clear, four-stage competitive bidding process.

In a broader sense, the disciplined unity that EU leaders have worked to build as part of the Brexit negotiating process seemed to have taken root and spread. And the overall sentiment Thursday was one of ambitious optimism. "That's the story: Europe is back," a senior Council official said. "We’re back in business."

While the Brexit talks had formally begun just three days earlier — and nearly two years of tough discussions appear to lie ahead — this week's summit in many respects appeared to mark the U.K.'s de facto departure from the bloc. Britain's muscle and influence seemed to have vanished in a puff.

"I told them that in fact the European Union was built on dreams that seemed impossible to achieve, so who knows?" — Donald Tusk

While U.K. Prime Minister Theresa May was allotted time during a working dinner to address other leaders, no time was allowed for response, as Tusk sought to block May from trying to use the Council forum to divide the remaining 27 nations or to advance Britain's negotiating aims.

Instead, Tusk planned for the 27 to discuss the issue of the agency relocations among themselves once May had left the group, part of the dual-track Council meetings that are now required since her formal triggering of withdrawal negotiations in March.

But far bigger symbolism was intended in the lack of focus on Brexit, as Tusk, Juncker and others sought to make good on their promise not to get distracted by the U.K. That pledge has only seemed more important since the dismal showing of May and her Conservative Party in British national elections this month that left her clinging to power and cast a cloud of uncertainty over her personal future.

Indeed, the EU is feeling so upbeat and so confident that Tusk, at a joint press statement with Ukrainian President Petro Poroshenko on Thursday morning, even allowed himself a public hope that the British might still change their minds.

"Some of my British friends have even asked me whether Brexit could be reversed and whether I could imagine an outcome where the U.K. stays part of the EU," Tusk said, a glint in his eye. "I told them that in fact the European Union was built on dreams that seemed impossible to achieve, so who knows?"

Tusk couldn't help but throw in a British musical reference. "You may say I am a dreamer," the former Polish prime minister said. "But I am not the only one."