I was wondering if, so shortly after the end of WWII, the inner six countries forming the ECSC experienced tensions between the former enemies (west-Germany and Italy vs. France, The Netherlands, Belgium and Luxembourg)? And, if there were tensions, how did they manifest? How were they dealt with?
If I recal correctly, a lot of the German leadership wasn't replaced after WWII and many functionairies remaind in their post. I can imagine this leading to tensions between former axis and allied leadership in trading etc
Some context:
1947: Marshall plan, US aid to Europe.
1948: OEEC (what would later become OECD) formed to administer aid.
1948: NATO created.
1949: Statute on the Council of Europe.
1950: European Convention on Human Rights signed.
In 1951, then, the treaty establishing the European Coal and Steel Community was signed.
In the words of Lord Ismay, the first Secretary General of NATO, the purpose of the alliance was "to keep the Russians out, the Americans in, and the Germans down".
Further attempts at integration during the 50s were not, however, primarily opposed by Germany which was divided by the iron curtain. 1948 had been the year of the Berlin airlift and Germany had good reasons to look westwards.
The tensions manifested itself in popular opposition and failures of further integration. The treaty establishing a European Defence Community, which had origins in French opposition to German NATO membership, would have a European army with a common budget and joint institutions. It was signed in 1952 by the six ECSC states, but Britain refused to participate. A European army, it was felt, would require a common European foreign policy of some sort, and for this reason the European Political Community was planned, with a bicamberal parliament with real legislative powers and an executive council and a court of justice. French public opinion would cause it to be opposed among both the left and the right of the National Assembly, however, and these immediate and far-reaching plans of the EDC and EPC would both fail.
Instead the European Economic Community was formed, with the creation of a single market and a very gradual and piecemeal approach to integration was started, much of it through the judicial, which would lead to the EU of today and is still continuing. This process has been rather opaque and legal-technical. Today, EU legislation supercedes member state constitutions, which was first decided by the European Court of Justice and only later put in to treaty more or less as a restatement of what was already law, as with many other things. Treaty articles have also been given effects in ways not very likely to have been originally intended or expected (for example horizontal direct effect between private legal subject A and private legal subject B). Member states would mostly devise opposition to this so-called "competence creep" (the EU is not supposed to have kompetenz-kompetenz, the competence to give itself more competence) either by simply not refering cases to the ECJ for help with interpretation, some almost never do it even though they are required to do so, or by claiming their respective constitutions provided protection of rights that EU law did not, since the European Convention of Human Rights, after all, is separate from and older than the EU, with it's own court. Hence it was felt that the EU needed its own charter of rights, which is why we now have both the European Convention of Human Rights as well as the EU Charter of Fundamental Rights, if by any chance you were wondering.