From 1939 to 1945, during theSecond World War, Carstens was a member of ananti-aircraft artillery (Flak) unit in theLuftwaffe, reaching the rank ofLeutnant (Second Lieutenant) by the war's end. In 1940 he joined theNazi Party; reportedly, he had applied for admission in 1937 to avoid detrimental treatment when he worked as alaw clerk. He had, however, joined the NaziSA paramilitary organisation already in 1934.
After the1976 federal elections, which made the CDU/CSU the largest group in parliament, Carstens was elected president of the Bundestag on 14 December 1976. The CDU/CSU had also reached a majority in theFederal Convention electing thePresident of Germany, and in 1979 the party nominated Carstens, though in contestation due to his Nazi past, as candidate, whereafter incumbent PresidentWalter Scheel (FDP) chose to renounce a second term.
On 23 May 1979, Carstens was elected as the fifth President of the Federal Republic of Germany, prevailing against the SPD candidateAnnemarie Renger in the first ballot. During his term of office, Carstens was well known forhiking Germany in order to decrease the gulf between politics and the people.
In December 1982, the new ChancellorHelmut Kohl (CDU), recently elected in a successfulmotion of no confidence againstHelmut Schmidt (SPD) deliberately lost a vote of confidence in the Bundestag, in order to obtain a clearer majority in new general elections. Though already former ChancellorWilly Brandt had similarly proceeded in 1972, this action gave rise to a discussion whether such a step constitutes a "manipulation of theConstitution". On 7 January 1983, President Carstens nonetheless dissolved the Bundestag and called for new elections. In February 1983 his decision was approved by theFederal Constitutional Court so that1983 general elections could take place on 6 March.
In 1984 Carstens decided not to seek a second term on account of his age and left office on 30 June 1984. He was succeeded byRichard von Weizsäcker.
^Due to the division of Germany, Walter Scheel was only the President ofWest Germany. The termWest Germany is the common English name for theFederal Republic of Germany between its formation on 23 May 1949 and theGerman reunification through the accession ofEast Germany on 3 October 1990.