I have tried to warn readers, in my columns, time and again, against the real risk of seeing Turkish-German relations getting out of hand. Well, get out of hand they have, unfortunately, in a very brusque and violent way. German Chancellor Angela Merkel, who is not known for her untimely declarations, has made a very alarming assessment recently. She declared peremptorily that the modernization negotiations of the customs union between Turkey and the EU should be reported, until "Turkey comes to its senses."

These negotiations and the need for modernization is of utmost importance for the good functioning of the customs union. Delaying them is a terrible mistake both for the EU and Turkey. Thinking that this could be just a negative political gesture against Turkey is a huge misstep that cannot easily be corrected in the foreseeable future.

When Chancellor Merkel made her unexpected and harsh declaration, half of the Turkish government members reacted publicly. It is understandable that the president or the premier responds personally to the chancellor, but when ministers start to answer personally, German ministers also do the same thing, and the whole situation turns into a very undiplomatic outcry, where everyone accuses everyone else of being totally wrong.

The German government does not really have the right to invoke a blunt intervention upon their national sovereignty, because practically the totality of their political elite took a very active stance regarding the recent referendum in Turkey. The stance taken by Turkey, regarding the vote of German citizens of Turkish origin is very hard to swallow also. But once the framework of diplomatic relations is broken, this is what usually happens. Such public disputation and exchange of invectives hardly resolves anything and leaves deep, hard-to-heal scars in international relations.

Nevertheless, what is essential in this whole political quagmire still remains the understanding of the customs union. This is not a conjectural "agreement" as most analysts seem to believe in. This has been one of the staunchest steps taken by the Republic of Turkey as early as in 1959, when Premier Adnan Menderes declared publicly that Turkey would side by the nascent European Economic Community.

The customs union is the final stage of our "association" with the EU that is ultimately supposed to turn into a full membership. The customs union started not in 1996, which is its completion date, but back in 1970 with the signing of the Additional Protocol. Already in 1971, the EU unilaterally dismantled its custom taxes concerning Turkish industrial goods. Our industry has been shaped up by the European (mostly German) technologic traditions. With the finalization of the customs union in 1996, through a simple but very detailed Association Council decision, the Turkish economy has been upgraded. Today's production instrument of the Turkish economy has been shaped up through harmonization with the immense Single Market regulatory framework. The competitiveness of our economy has been solidly established through its liberalization within the scope of our harmonization to the EU.

But much more than that, a customs union never remains final in itself. Two countries, or a number of different countries, or regions, or just plain economies decide to form a customs union, because they share a similar perspective for their future. The German reunification has started with the Zollverein, a customs union, before becoming a political reality. The European integration, which is practically the only successful achievement of the European civilization, who committed suicide through two world wars, has been based on a customs union. Article nine of the original Treaty of Rome defines clearly the bedrock of this integration.

Briefly, a customs union is the backbone of a shared vision and collaboration among countries. It is a social contract between regimes that are similar and constitutes a promise, an engagement of development and cooperation for the future generations. I am not sure whether this essential aspect of our cooperation is really understood by the German political elite. Managing ephemeral crises should not give way to long-lasting structural conflicts. This is essential not only for Turkey, but also for Germany and for its Turkish diaspora.