Later, the constitution was amended to state that the citizens of the 16 states had successfully achieved the unity of Germany in free self-determination and that the Basic Law thus applied to the entire German people. Article 23, which had allowed "any other parts of Germany" to join, was rephrased. It had been used in 1957 to reintegrate the Saar Protectorate as the Saarland into the Federal Republic, and this was used as a model for German reunification in 1990. The amended article now defines the participation of the Federal Council and the 16 German states in matters concerning the European Union.

What was the German constitution later amended to say about the citizens of the 16 states?