SPD leader and Chancellor Willy Brandt remained head of government until May 1974, when he resigned after the Guillaume Affair, in which a senior member of his staff was uncovered as a spy for the East German intelligence service, the Stasi.
Pemimpin SPD dan Kanselir Willy Brandt tetap menjadi kepala pemerintahan sampai Mei 1974, ketika ia mengundurkan diri setelah Perselingkuhan Guillaume , di mana seorang anggota senior stafnya ditemukan sebagai mata-mata untuk badan intelijen Jerman Timur, Stasi .