Rainer Barzel, a veteran conservative leader whose attempt to topple former Chancellor Willy Brandt was allegedly undermined by the East German spy service, has died. He was 82.

As chairman of the Christian Democrats from 1971 to 1973, Barzel helped force a vote of confidence against then-West German Chancellor Brandt, a Social Democrat.

Barzel, a strong advocate of German reunification, opposed Brandt’s efforts to seek reconciliation with communist East Germany and the Soviet Union.

The conservatives lost the 1972 vote narrowly and Brandt also defeated Barzel in national elections later the same year. Barzel gave up the leadership of the Christian Democrats and their parliamentary group in 1993.

Markus Wolf, the former head of the East German Stasi secret service, said later that his operatives had bribed at least one conservative lawmaker not to vote against Brandt.

Barzel, who was born in the former German territory of East Prussia, now Poland, and served in the Luftwaffe during World War II, was a strong advocate of German reunification.

He served from 1982 to 1983 as Minister for Inner-German Questions in the Cabinet of ex-Chancellor Helmut Kohl.

He was elected parliamentary president in 1983, but resigned the following year after being caught up in a scandal over payments by a company to various political parties.

He withdrew from parliament in 1987 after 30 years, including 10 as Christian Democrat faction leader.