While Article 24 of the NSDAP party platform called for conditional toleration of Christian denominations and the 1933 Reichskonkordat treaty with the Vatican purported to guarantee religious freedom for Catholics, the Nazis were essentially hostile to Christianity and the Catholic Church faced persecution in Nazi Germany.
Its press, schools and youth organisations were closed, much property confiscated and around one third of its clergy faced reprisals from authorities.
Prior to 1933, Catholic leaders denounced Nazi doctrines while Catholic regions generally did not vote Nazi.
The Center Party's attitude had become crucial since the act could not be passed by the Nazi and DNVP coalition alone.
It marked the transition in Adolf Hitler's reign from democratic to dictatorial power.
In early 1933, following Nazi successes in the 1932 elections, lay Catholic monarchist Franz von Papen, and acting Chancellor and Presidential advisor, General Kurt von Schleicher, assisted Adolf Hitler's appointment as Reich Chancellor by President Paul von Hindenburg.
In March, amidst the intimidating atmosphere of Nazi terror tactics and negotiation the allied BNVP and the monarchists DNVP voted for the Enabling Act.
Mary Fulbrook wrote that when politics encroached on the church, Catholics were prepared to resist, but that the record was otherwise patchy and uneven, and that, with notable exceptions, "it seems that, for many Germans, adherence to the Christian faith proved compatible with at least passive acquiescence in, if not active support for, the Nazi dictatorship".
Catholics fought on both sides in the Second World War.
His first encyclical, Summi Pontificatus, called the invasion of Poland an "hour of darkness", his 1942 Christmas address denounced race murders and his Mystici corporis Christi encyclical (1943) denounced the murder of the handicapped.
In the 1930s, Catholics constituted a third of the population of Germany and "Political Catholicism" was a major force in the interwar Weimar Republic.
Popes Pius XI (1922–39) and Pius XII (1939–58) led the Roman Catholic Church through the rise and fall of Nazi Germany.
Around a third of Germans were Catholic in the 1930s.
While Nazi antisemitism embraced modern pseudo-scientific racial principles, ancient antipathies between Christianity and Judaism contributed to European antisemitism.