PARIS β€” As the United Kingdom chaotically prepares for Brexit, and while Italy and Poland continue to distance themselves from European values, the Franco-German partnership is β€” if only by default β€” increasingly indispensable. Because really, who else is there to rely upon? Spain has taken undeniable steps in the right direction, but it doesn't have the critical mass to make things happen, especially while it remains absorbed with the Catalan separatist problem. And the other European countries have neither the means nor the ambition to play a leading role. Nature abhors a vacuum. So does Europe.

But even though the relationship between Berlin and Paris is more essential than ever, it's also more fragile, given the weakening of power in both countries. For decades, the Franco-German pairing, supported by a spirit of reconciliation embodied in symbolic duos β€” Charles de Gaulle-Konrad Adenauer, Francois Mitterrand-Helmut Kohl β€” made Europe "work" and move forward. The other members of the Union could, from time to time, express their frustration in the face of what they sometimes considered to be a diktat. But economic growth, on the one hand, and the Soviet threat, on the other, encouraged them to overcome their mood swings.

Things began to change when Germany reunified, and when the Union began to expand. It's indeed easier for two countries to impose their views on a club of six to 15 members than on a group of 28 (soon to be 27) that has inherent difficulties creating a common culture. What's more, the balance of imbalance that existed between a more dynamic and economically prosperous Germany and a more politically and strategically central France had faded over the years. With the disappearance of the USSR and with their own peaceful reunification, the Germans felt that the "End of History," as announced by Francis Fukuyama, confirmed the relevance of their choices.

If economic power had become more important than military might, Berlin's "soft power," embodied by reassuring leaders and benefiting from their longevity in power, could only prevail over France's "hard power," embodied by presidents challenged by their electorate. This vision gradually changed from 9/11 onwards, but Germany did not draw all the budgetary consequences from the return of the "tragic of History."

Over the past few months, the Franco-German relationship has undergone upheavals. There was, first of all, hope it was for the better until fears it was for the worse started to rise. It's not that the two countries have moved away from one another. It's above all that they, first of all, haven't moved closer to one another and that they weakened politically on their own afterwards. Germany's unemployment rate, which still stands at around 3.4%, contrasts sharply with France's, which seems structurally fixed at around 9%.

As far as geopolitics are concerned, however, history β€” after ruling, it appeared, in Berlin's favor β€” now seems to shift towards Paris. Geopolitical considerations have regained their priority. Brilliant export figures and spectacular budget surpluses are not the answer to strategic challenges. At a time when America is combining a nationalist explosion and isolationist temptation, "Paris' cards" are probably more appropriate than Berlin's. France and Germany can speak with almost the same voice on defense or the European army, but in reality, their "cultures" in this respect remain profoundly different. France is suffering from no longer being a great nation while Germany still fears becoming, once again, a great power.

Can you be ambitious for Europe when you're challenged in your own country?

Today we are rediscovering, albeit under another form and wording, what once made a fundamental difference in the two countries' approaches towards Europe. For Paris, Europe was the card that allowed France to remain itself by other means. It was, in other words, a tool of power and influence. For Bonn, and later Berlin, Europe was, on the contrary, a tool of control, if not self-control, over Germany.

Overcoming this fundamental disparity in our respective approaches to Europe is made even more difficult by the weakening of the political elites in power on both sides of the Rhine. Angela Merkel is no longer what she was and Emmanuel Macron isn't perhaps becoming what we'd hoped he would be.

His surprise victory in 2017 seemed to signal a necessary rebalancing between the two countries. It's not that there was too much Germany. Rather, there wasn't enough France, and this may have been the case since at least 1995 and the end of the Mitterrand presidency. In the late 1980s, political scientist Pierre Hassner described the U.S./USSR relationship as a process of competitive decline between the two countries. One would be tempted to describe the current political relationship between France and Germany with the same wording. There is, however, one major difference. This is not a zero-sum game. Berlin's weakness is a handicap for Paris and vice versa.

The question for Emmanuel Macron and Angela Merkel is the following: Can you be ambitious for Europe, rallying a majority of citizens behind you, when you're strongly challenged in your own country?

Contrary to what one might think, the answer is "yes," inherently yes. Europeans may no longer like Europe, but they are nonetheless aware that, in an ever more dangerous world, they need it β€” provided they feel protected by it. It would be unfortunate if the 1990s dream of the "End of History" were to give way in 2019 to an "End of Hope". That, to put it in other words, would be the twilight of the European project.

See more from Opinion / Analysis here