Many things divide the 27 member states of the European Union these days, but one controversy in particular sums up the bloc’s fundamental dilemma. It is over “enlargement”, and specifically whether to formally start accession talks with North Macedonia and Albania. Seething below the surface is the question of whether the EU can, in Eurocrat jargon, keep “widening” and “deepening” at the same time.

Put differently, if the EU keeps admitting new members, whether they are ready or not, will it not just become ungovernable and drift apart?

As usual, it fell to French President Emmanuel Macron, who has earned himself quite a reputation for being undiplomatically honest, to point out this tension. He shocked other EU leaders by blocking formal talks with North Macedonia and also, supported by only Denmark and the Netherlands, Albania. German Chancellor Angela Merkel, among others, was irate; the Balkans were livid. The EU is now scrambling to get him to drop his veto before the European Summit next month.

Two main arguments were hurled at Macron. First, that he was being unfair in failing to recognise how much the two countries have already done to become good candidates. Albania has cleaned up its judiciary and cracked down on organised crime. The other country even changed its name — adding “North” — just to appease EU member Greece, which has a region that argued it had dibs on “Macedonia”. The EU had promised that this would be enough to start negotiating.

Second, Macron was accused of being strategically myopic, just when the EU needs to start thinking “geopolitically”. Russia and China are already extending their tentacles into southeastern Europe, the latter by financing ports, bridges and rail lines as part of opaque political deals. If the Balkans feel spurned by the EU, they will run, rather than walk, into the arms of non-Western autocrats.

All true. But there is also a good reason for objecting to enlargement: it inevitably gums up integration between the EU’s existing members. Working together was hard enough among the six founding countries back in the 1950s. With each new entrant, it kept getting harder yet, as new languages, political cultures, historical grievances and national interests had to be accommodated. This was true after Britain joined in 1973 — and look where that led — and after the Mediterranean and Nordic expansions later.

The dilemma became especially clear after the two eastward expansions in 2004 and 2007. The same arguments were being used then as now: not admitting the post-communist nations would have been geopolitical folly, stranding them in the sphere of influence of their former Russian oppressors. And it would have been unfair to people who had long and valiantly struggled for their freedom and yearned to join “the West”.

More than a decade on, however, and some of those eastern members have turned into spoilers of the European project, or worse. Hungary is a quasi-autocracy that proudly calls itself “illiberal”. Poland is actively undermining the independence of its judges and the rule of law, in open confrontation with the European Court in Luxembourg. Both are obstructing any progress in formulating a common European policy for dealing with migrants. In effect, they have rejected the EU’s founding idea of European solidarity in favour of an atavistic nationalism.

Each previous round of enlargement thus introduced new fractures into the EU, some between north and south, others between east and west. Macron is hardly alone in observing that European integration stalled long ago, and that “widening” had something to do with that. In foreign and defence policy, any member state can veto any decision, thus assuring European irrelevance and impotence on the world stage. Bigger ideas such as a European army are nothing more than pipe dreams. In the euro area, neither banking nor fiscal union has been completed, thus leaving the currency union prone to another crisis.

All of this is part of thinking geopolitically. Without a euro to rival the dollar, without diplomats or soldiers that Turkey, Russia, China and others take seriously, what good will the EU be in the long run?

On balance, it’s still better to open talks with Tirana and Skopje than to reject them. But the EU must simultaneously confront the bigger dilemma of stalled integration. For that, it has to broach a taboo and talk about a multi-speed Europe.

The idea has been around for decades: letting some groups of countries integrate faster than others in policy areas they choose. To a large extent, that is already a reality. Only 19 out of 27 EU countries share the euro; 26 members of the so-called Schengen area have completely open borders with one another, of which four — Norway, Iceland, Switzerland and Liechtenstein — are not even in the EU. And so on.

Why should some members — Germany, Luxembourg and the Netherlands, say — not now advance to fiscal union, allowing others to join later? Ditto in foreign, defence and migration policy. If the EU as a whole can’t deepen, let parts of it do so.

Some member states, such as Poland, have always opposed such a tiered EU, afraid of becoming peripheral and second class. And yet they claim to be equally worried about ceding more sovereignty to Brussels. But that is the choice inherent in belonging to the EU.

So let’s make the club flexible, with different kinds of membership. Let’s not call them gold, sliver and bronze, but something like deep, medium and shallow. With different tiers come different degrees of integration, obligations and rights. You don’t want to take your share of refugees? Then you get less from the EU budget. You don’t believe in rule of law? Then you lose your votes in Brussels.

In such a flexible EU, parts of Europe could coalesce into powers with geopolitical heft, while other parts retain more independence. This is the only way Europe can deepen and widen at the same time. Who knows? Maybe that is the kind of EU even the British may want to join one day.

• This column does not necessarily reflect the opinion of Bloomberg LP and its owners. Andreas Kluth is a member of Bloomberg’s editorial board. He was previously editor-in-chief of Handelsblatt Global and a writer for The Economist