The European Union has been aiming to strengthen ties between its countries’ armies since 2007. This week, it finally took a concrete step towards that, with 23 of the bloc’s 28 member states signing a defense pact.

But while European figures didn’t hold back on the rhetoric at the signing ceremony for the wonkily-named agreement on “Permanent Structured Cooperation,” known as PESCO, experts told Quartz that the defense pact is far from creating a so-called “EU army” or even tangibly strengthening Europe’s security.

“We’ve heard all this before,” said Judy Dempsey of Carnegie Europe think tank.

EU foreign affairs chief Federica Mogherini called it ”historic.” German foreign minister Sigmar Gabriel called it a “milestone in European development.” European Commission chief spokesman Margaritis Schinas even evoked the lunar landings, dubbing it (paywall) a “small step for Brussels, a giant leap for Europe.”

And yet, they gave very little sense of what it actually does beyond the buzz-phrase of “defense cooperation.” The aim is to “jointly develop defense capabilities, invest in shared projects and enhance the operational readiness and contribution of their armed forces,” the Commission wrote in a cryptic statement.

Quartz spoke to Dempsey and two other experts to get a sense of what the agreement means and why it’s happening now.

Fuelled by external pressure

There are reams of outside factors pushing Europe to integrate on defense. Repeated terrorist attacks on European soil in recent years have shown up the continent’s vulnerability. Its inability to control who enters its borders during the height of the refugee crisis in 2015 and 2016 was a huge wake-up call. Russia’s invasion of Crimea and the proxy war with Ukraine showed a renewed threat from the East.

Then Donald Trump became US president and made the EU really sit up and take note. Trump had previously called NATO “obsolete” during his election campaign, and spoke evasively over his support for the alliance’s cornerstone Article Five clause which decrees that “an attack against one ally is considered an attack against all.” ”There’s a sense among European capitals… that Europe can’t take the American security umbrella for granted,” says Dempsey.

On top of that, Britain’s impending departure from the EU meant it was easier for the bloc to sign. While the UK started to warm to the EU’s defense pact, there were many years of protests from British lawmakers over the EU creating a more unified military unit. But while it was now easier to sign, the lack of UK involvement means the loss of what many consider its most effective military power.

That means France is now the only serious force in the bloc—something the French are very concerned about, says Mark Galeotti of the Institute of International Relations Prague. “Britain was the key hard power provider to the EU—particularly in terms of intervention capabilities,” he says. That’s left France desperate to share the burden with other European allies.

Beyond actual defense, Brexit has also made people at the heart of Europe want to be seen to be moving the continent forward. “There’s this real drive on the part of [France and Germany] to show that the EU works, and that it’s a project which delivers on the issues that are important to European voters,” says Susi Dennison, of the European Council on Foreign Relations.

What does PESCO actually do?

Right now, not that much—certainly a long, long way from the European army that British tabloids began proclaiming. “It’s really a framework to try and make cooperation easier but it doesn’t actually create any cooperation in itself,” says Galeotti.

In other words, it’s aspirational.

The first broad aim is to make European armies readier to slot alongside each other on joint missions if and when needed, and to integrate even further where possible. This already happens on a small scale, with a few forces highly melded in various fields. Germany, Denmark, Poland, and the Czech Republic have some integration in their ground forces, as do the Brits and Dutch with their air forces. Belgium, the Netherlands, and Luxembourg have a highly integrated navy.

Doing more of this sounds great in principle, says Dempsey. “But you’re going to need much more than PESCO to make this work. The EU needs a proper command structure and a military headquarters,” she said. “The leaders of institutions and member states have to explain to their publics why we need proper European security and defense otherwise PESCO won’t get off the ground.”

The second big goal is to work together on procurement to avoid the current wasteful situation where 28 member states often buy equipment from 28 different suppliers. They’ll be backed by a €5.5 billion ($6.5 billion) annual defense fund announced last year, aimed at stopping that kind of duplication. But few expect things to dramatically change, with arms manufacturers a crucial force in each country’s economy.

“Let’s take the classic example of small arms,” says Galeotti. “The Czechs produce really quite good rifles; so do the Germans and Italians, as do others. It’s not like at all likely that the Czechs will say, ‘That’s a fair cop, we’ll buy other rifles and screw over own industry.’ Let alone that the Germans will say, ‘We’ll buy Czech rifles.'”

However, he notes that there is scope to work together on equipment that no European nation provides, pointing out that no one makes fifth-generation fighter planes in Europe, whereas the US, Russia, and China all do.

None of this is to say PESCO is doomed from the start. “The potential is big but now they have to deliver something,” says Dempsey, arguing that developing a coherent security plan in the Western Balkans, where NATO does all the heavy lifting, would be a sign of genuine intent.

“They’ve skirted around this issue; they don’t like bringing it up. But if we want military cooperation, we have to face very hard issues,” she added.

What are the geopolitical effects?

Announcements like this are exactly what Washington foreign policy elites want to hear, confirming that Europeans are finally reckoning with their own security needs.

“From the EU side there’s a sense that Trump is right, that Europe does have to take responsibility for itself,” says Dennison. “It has accepted that the ambition of getting closer to [spending] 2% of GDP on defense is something that European states need to start taking more seriously.”

Surprisingly, it’s also music to the Russians’ ears. “Russian defense types are all in favor of a European army because they reckon, not without reason, that it would undermine NATO,” says Galeotti, a Russian security expert. “PESCO doesn’t create a European army—it’s a long way from that, but actually from the Russian point of view it would actually create fissures between Europe and NATO.”

Perhaps with an eye to this, the launch was well-coordinated, with NATO secretary-general Jens Stoltenberg openly welcoming the initiative. Steps like this don’t represent a real threat to NATO but if the project does keep going, “the Europeans will have to be very very clear on what they have to use it for; if it’s to be a competitor to NATO forget it—that would be highly dangerous,” says Dempsey.