オーデル・ナイセ線
In March 1990, the West German Chancellor Helmut Kohl caused a storm, when he suggested that a reunified Germany would not accept the Oder–Neisse line, and implied that the Federal Republic might wish to restore the frontier of 1937, by force if necessary. Kohl further added that in a statement of 1 March 1990 that he would only recognize the Oder–Neisse line if Poland promised to pay compensation to the Germans expelled after 1945 and if Poland promised not to seek reparations for the sufferings of Polish slave labourers in Germany and reparations for the damage done by German forces to Poland during World War II. After Kohl's note caused a massive international backlash that threatened to derail the process for German reunification, Kohl hastily changed track, and said that a reunified Germany would accept the Oder–Neisse line after all, and that he would not seek to link recognizing the Oder–Neisse line to talks about compensation. In November 1990, after German reunification, the Federal Republic of Germany and the Republic of Poland signed a treaty confirming the border between them, as requested by the Treaty on the Final Settlement With Respect to Germany. Earlier, Germany had amended its constitution and abolished Article 23 of West Germany's Basic Law (on which reunification was based), which could have been used to claim the former German eastern territories.