Deckers was elected to the
House of Representatives in the
1918 general election, taking office on 17 September 1918. After the
1929 general election Deckers was appointed as
Minister of Defence in the
Ruijs de Beerenbrouck III cabinet, taking office on 10 August 1929. After the
1933 general election Deckers returned to the House of Representatives, taking office on 9 May 1933. Following the
cabinet formation of 1933 Deckers continued as Minister of Defence in the
Colijn II cabinet, taking office on 26 May 1933. The cabinet fell on 23 July 1935 and continued to serve in a demissionary capacity until the
cabinet formation of 1935 when it was replaced by
Colijn III cabinet with Deckers remaining as Minister of Defence, taking office on 31 July 1935. Deckers was appointed as
Minister of Agriculture and Fisheries after the Ministry of Economic Affairs was split into the
Ministry of Commerce, Industry and Shipping and the
Ministry of Agriculture and Fisheries, taking office on 2 September 1935. After the
1937 general election Deckers again returned to the House of Representatives, taking office on 8 June 1937. Following the
cabinet formation of 1937 Deckers was not giving a cabinet post in the new cabinet; the Colijn III cabinet was replaced by the
Colijn IV cabinet on 24 June 1937 and he continued to serve in the House of Representatives as a
frontbencher. Deckers was selected as party leader and
parliamentary leader of the Roman Catholic State Party in the House of Representatives following the election of
Josef van Schaik as a
Speaker of the House of Representatives, taking office on 11 November 1937. On 10 May 1940
Nazi Germany invaded the Netherlands and the
government fled to London to escape the
German occupation. During
World War II Deckers continued to serve in the House of Representatives but in reality the
de facto political influence of the House of Representatives was marginalized. On 9 October 1940 Deckers was arrested and detained in
Buchenwald concentration camp and was released on 7 November 1940. Deckers also served retroactively as chairman of the
Roman Catholic State Party from 1 September 1941 after
Timotheus Verschuur was detained in
Sachsenhausen concentration camp and later died in captivity on 17 April 1945. In May 1942 Deckers was arrested and detained again in Buchenwald concentration camp and was released in August 1942. Following the end of World War II
Queen Wilhelmina ordered a
Recall of Parliament and Deckers remained a member of the House of Representatives, taking office on 20 November 1945. On 22 December 1945 the Roman Catholic State Party was renamed as the Catholic People's Party, Deckers was one of the co-founders and was selected as the first parliamentary leader of the Catholic People's Party in the House of Representatives. In March 1946 Deckers was nominated as member of the
Council of State, he resigned as parliamentary leader and as member of the House of Representatives the day he was installed as a member of the Council of State, serving from 1 April 1946 until 1 March 1958. ==Decorations==