Many Europeans immediately took the Brussels bombings on Tuesday as an assault on Europe itself. After all, the Belgian capital has long been synonymous with the European Union, and one bombing target was a metro station just steps from major EU institutions.

French President François Hollande declared, “The whole of Europe has been hit.” Germany’s Der Spiegel titled its lead story “Terror hits EU power center.” Declarations of solidarity clogged the Internet from across Europe.

Assuming that the collective Europe has been attacked, can it respond as one?

“No,” said John Kornblum, a former U.S. ambassador to Germany still based in Berlin. “Europe is dysfunctional,” he said. “A response is not just tightening border control but coming up with a security strategy. Up to now, to be Europe meant to be more peaceful than everybody else.”

Kornblum, who has been involved in trans-Atlantic relations since the 1970s, speaks out of frustration, not schadenfreude. Europeans are the first to admit that big strides in the European Union’s political and economic integration have outpaced cooperation in law enforcement and security.

There still isn’t a common database that contains the names of all terrorism suspects and Europeans who have joined organizations like Islamic State, Peter Neumann, a security expert at London’s King College, said on German ARD television Tuesday night.

“Everybody wants information from others,” Neumann said, “but nobody wants to share. Everybody wants coordination, but nobody wants to be coordinated. If you want freedom of movement in Europe, you also need to ensure the seamless cooperation among security agencies.”

Just as the Greek debt crisis exposed the inadequacies of the euro — namely, the absence of an overall European fiscal policy — the terrorist attacks in Paris and Brussels demonstrate the shortcomings of borderless travel.

The 1990 Schengen Agreement opening EU internal borders was eventually signed by 26 European countries to encourage wider mobility and trade. The possibility that terrorists or undocumented migrants might take advantage of the Schengen area didn’t fit into the image of an enlightened postwar Europe. Now, the refugee crisis is showing that the European Union barely controls its external borders.

Different rules that govern competing local and national law enforcement agencies make a coordinated response to the Brussels attack complicated. Another challenge is that the traditionally separate areas of domestic security and external defense have become blurred by international terrorist networks.

In the past, terrorism in Europe was largely seen in terms of national threats from groups such as Basque separatists in Spain or the Irish Republican Army in Britain. The emergence of al Qaeda and Islamic State changed that view dramatically, said Nicolas Tenzer, head of the Center for Study and Research on Political Decision, a Paris think tank.

Europe, Tenzer said, is unlikely to react to the Brussels attacks as a whole. Yet, the major powers — including Britain, France, Germany and the Netherlands — will probably step up cooperation, Tenzer said, adding that it’s important to distinguish between the exchange of information and operational cooperation.

“Ad hoc operations are already possible between police departments,” he said. “But large-scale cooperation, as it sometimes exists on the battlefield, may be more difficult with many countries.”

The crux of Europe’s quandary in fighting global terrorism mirrors its problems with a shared foreign policy or common currency: a reluctance to sacrifice even more sovereignty on the altar of EU unity. Add Europe’s lack of tactical capabilities and increased U.S. isolationism, and Europe begins to look vulnerable.

“It’s very dangerous for Europe because they need the United States,” said Kornblum, the former diplomat. “They’ve been neglecting security interests for at least 10 years.”

President Barack Obama, in a recent Atlantic magazine interview, criticized European powers as “free-riders” because of their dependence on Washington for security. Donald Trump, front-runner for the Republican presidential nomination, echoed that sentiment this week as he questioned the billions of dollars the Pentagon spends on defending such wealthy countries as Germany.

The United States does in fact play a crucial role for European security. It is key not only in intelligence gathering but in its ability to deliver military strikes around the world.

“Better police work, coordinated among EU members, must certainly be one part of the answer,” said Ulrich Speck, a senior fellow at the Transatlantic Academy in Washington. “But the other part has to do much more with Syria. With such a devastating war in its immediate neighborhood, Europe cannot live in peace.”

The conflict in Syria helped create the current refugee crisis and is one source of the extremism espoused by terrorists in Europe. Yet, the European Union has neither the will nor the means for deeper engagement in the Middle East.

“Berlin and Paris should jointly take the lead, in close cooperation with London,” said Speck. “But so far they’re just waiting for Washington. The United States is unwilling to commit serious resources — and is geographically too far away to feel the spillover effects.”

Europe’s failure to come up with a consolidated response to terrorism bears risks not just for the European Union, but also for the entire postwar trans-Atlantic alliance.

“It’s not only a question about EU institutions, but about trust in the system,” said Roderich Kiesewetter, a member of the German parliament’s committee on foreign affairs. “It’s also a psychological question.”

Given existing centrifugal forces in the European Union, citizens may lose even more faith if they don’t see an effective EU reaction to terrorist attacks, Kiesewetter said, which could push many to support parties on the political extremes. What’s more, if Washington becomes engrossed in its own affairs, some forces in Europe might well seek closer accommodation with Russia.

For trans-Atlanticists, a European response automatically becomes an American one as well.