But despite a recent amendment by the German federal government, the law still guarantees Lower Saxony's veto.

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Radical groups like the National Democratic Party (NPD), which the German federal government has unsuccessfully tried to ban, have gained a platform, especially in eastern regions, in recent years, Rodig said.

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The city of Berlin and the state of Brandenburg are the main parties involved in the construction of the airport, with the German federal government also footing part of the bill.

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