グレゴール・シュトラッサー
After his resignation, Brüning was invited by Ludwig Kaas to take over the leadership of the Centre Party, but the former chancellor declined and asked Kaas to stay. Brüning supported his party's determined opposition to his successor, Franz von Papen. He also supported re-establishing a working parliament by cooperating with the National Socialists, negotiating with Gregor Strasser.