The Social-liberal coalition of SPD and FDP had lost its majority after several Bundestag MPs (like former FDP ministers Erich Mende and Heinz Starke or SPD partisan Herbert Hupka) had left their party and become members of the CDU/CSU opposition to protest against Chancellor Willy Brandt's Neue Ostpolitik, especially against the de facto recognition of the Oder-Neisse line by the 1970 Treaty of Warsaw.

Rumours that at least one member of the CDU/CSU faction had been paid by the East German Stasi to abstain (in effect, voting against Barzel) were confirmed by Markus Wolf, former head of the Hauptverwaltung Aufklärung, in 1997.

[citation needed] Nevertheless, the following budget debates revealed that the government's majority was lost and only the upcoming organisation of the 1972 Summer Olympics in Munich delayed the arrangement of new elections.

He gained the support by numerous celebrities of the West German culture and media scene (e.g. Günter Grass), expressed by the slogan Willy wählen!

His Cabinet Brandt II returned to government the next day, again with FDP chairman Walter Scheel as vice-chancellor and foreign minister.