I lived in the UK during the early, heady years of European Union integration, when the borders were newly opened, the euro just introduced, and the subsidies still merrily flowing. Back then, everyone seemed to envision it as a sort of giant Club Med — a place to have nice vacations and the occasional broadening cultural experience.

To the extent that membership in the EU came with obligations, they were presented as something along the lines of polite social commitments, as if joining the euro were akin to extending a dinner invitation to friends because they had you over last month and it would be rude not to return the favor. There was a distinct lack of acknowledgement that all that togetherness and integration could come with truly burdensome obligations, or with unsettling political or social change.

But now we know that's not right: Integration brings many important benefits, but it is often also painful and difficult. And the events of this summer are making it very clear that after all these years, the EU's citizens and institutions are still unprepared to make the collective sacrifices or difficult choices that may ultimately be necessary to see integration through. And that's a problem, because what's happening in Greece could be just the tip of the iceberg. There are more problems to come.

The costs of integration

While EU integration brought opportunities, it also came with major consequences that couldn't be solved by individual countries alone.

The most prominent of these crises, currently, is the Greek debt crisis, which happened in large part because the EU, Greece, and global markets failed to come to a clear understanding about whether the eurozone would insure Greece's sovereign debt. That let Greece borrow at unsustainable levels, leading to a financial crisis that threatened the whole EU.

While Greece certainly should not have borrowed more than it could repay, this was always really a political problem, not an economic one: It arose because there was a market perception that the EU would guarantee eurozone countries' borrowing, but no corresponding political support for that among EU countries or the EU electorate. In other words, there was no clear rule in place about which responsibilities fell to the EU as a whole and which ones fell to individual countries.

And instead of clarifying the rules one way or another at the beginning, the EU waited until 2010, when the crisis was already well underway, before setting up stabilization mechanisms to share the burden of ensuring financial stability across the EU. Even that was too little, too late — as this week's events in Greece have shown.

Yet as serious as that crisis is, it's not going to be the only one — and there's no sign that Europe will be any better at dealing with the next crisis, or the one after that, than it was at dealing with Greece's economic catastrophe.

The other Greek crisis

Take, for instance, the "other" Greek crisis: the thousands of refugees and undocumented immigrants who are crossing the Mediterranean in ever-greater numbers to reach European shores. A record 1,600 people arrived on the Greek island of Lesbos last weekend alone, the BBC reports, and over 15,000 others arrived in June, more than double the number who arrived in June 2014. The influx has overwhelmed the island, which has a permanent population of only 86,000 people. Other parts of Greece, as well as Italy, are facing a similar crisis.

The immigrants aren't coming to Lesbos or Lampedusa for the beautiful beaches. Rather, they're coming because those islands are the most accessible parts of Europe to reach by boat, and desperate refugees believe the EU offers them the best hope of a better, safer life free from the persecution and violence they're fleeing. But once again, the EU seems to have been taken by surprise by an utterly predictable situation, and is responding by treating it as a problem for individual member states to deal with, rather than a problem for the EU to deal with as a whole.

Under the EU's Dublin Regulation, refugees have to stay in the first European country they arrive in until their claims are processed. In practice, that means that because Greece and Italy happen to be the most geographically accessible, they are largely on their own in dealing with the humanitarian crisis. The EU is treating the influx into Greece as a Greek problem and the influx into Italy as an Italian problem. In other words, it's as if the United States had regarded last summer’s mass arrival of child migrants at the US-Mexico border as a purely local issue to be handled by the state governments of Texas and Arizona.

Italian President Matteo Renzi has threatened that if the EU did not offer more help, Italy might issue visas to undocumented migrants en masse, allowing them to travel to other European countries. But so far, other EU countries are not really taking on their share of migrant burden. They're not helping because, quite simply, they don't want to and they don't have to. That's not really how the EU is supposed to work, and Renzi's threat gets to the heart of that contradiction.

Why these crises don't bode well for the future

In a sense, this isn't surprising. It was in EU leaders' interest to present the EU as a pleasant adventure rather than as a challenging political project that offered high rewards in exchange for difficult changes.

An EU of better roads, better food, better vacations, and fewer wars sounds good to everyone. An EU in which individual countries' problems become all of Europe's problems is a much harder sell. You don't get the former unless you also do the latter. But that's a hard sell politically, so European leaders downplayed it.

That turned out to be a good way to convince Europeans to sign up for the EU. But it has meant that Europe never developed the political capital or the political tools to actually deal with difficult problems like debt or migrant crises. It has no taxing authority of its own, which makes it difficult for the EU to solve problems that require a large amount of money. The EU governance process is cumbersome, requiring the unanimous assent of all member states for many types of decisions, which makes it very difficult to respond to major problems in real time.

Now the difficult problems are here, and Europe doesn't know how to deal with them. This is a core, systemic problem in the European project that, if it remains unsolved, will continue contributing to crises. The current Greek crisis could be just the beginning of a long string of EU catastrophes.