Political Christianity has a long history within German politics and religious matters was one of the perennial third rails for many German politicians ranging from Bismarck to Brandt. The current CDU is a byproduct of this highly complex relationship between politics and religion. The advent of the CDU in the immediate aftermath of the Second World War was the confluence of both long-term political trajectories in German democratic politics and the immediate context of the postwar occupation.

Religious affiliation in Germany often melds multiple layers of identity ranging from national, regional, and confessional. This made for some confusing politics. For example, while Rhenish and Bavarian Catholics managed to forge some common ground in the Kaiserreich's electoral politics, there was an antipathy in these groups to Silesian and Polish Catholics on the grounds that these co-religionists were not fully German. The result was that while the Centre, the main Catholic party, vigorously defended Catholic imperatives over schooling in southern and southwestern Germany during Bismarck's Kulturkampf, the Centre's leadership was conspicuously silent when the state later clamped down on Polish education and the Polish church. While Centre's press organs portrayed the Kulturkampf as a case of Prussian/Protestant tyranny against non-Protestant Germans, the Centre's press was indifferent to many of the same measures directed against coreligionist Poles.

Despite the hostility of the central government, the Centre had become one of the major political powers in the Reichstag. As seen in this map of the 1912 federal elections, the Centre had very strong regional bases in southern and western Germany. German Protestants tended to gravitate into a broader spectrum of political parties ranging from the more traditional liberal parties to recent upstarts like the antisemitic Christian Socials. But Catholic success had its own set of perils. Catholic doctrines like papal infallibility also became unwelcome millstones around the necks of Catholic politicians. The metaphor for Centre power- the Turm (Tower)- in both Weimar and the Kaiserreich was thus quite apt. Hewing to a confessional-based politics did give the Centre a strong voting base, but limited its appeal. Like many good fortifications, the Turm also had the potential to become a prison for its occupants.

This dissipation of the Protestant votes and the shrinking power of the Centre imparted a dubious legacy for political Christianity during the Weimar years. The Centre remained strong and organized throughout the Republic, but was never powerful enough to lead a government on its own. Its strength waned in areas such as the Rhine and even in its stronghold of Bavaria. The Centre's confessional identity made it much more difficult to appeal to non-Catholics and keep Catholic voters in the fold as secularization made inroads into society. There were individuals within the Centre's leadership that wanted to recast the party into a more interdenominational entity, but these efforts came to naught. All of this meant that while the Centre voting bloc proved to be an obstacle to the Nazi takeover in the 1930s, it was never able to articulate an alternative vision in defense of the Republic or forge practical alliances with other parties.

The experience of the churches under National Socialism only hardened this desire for greater interconfessional unity. While the record of German churches during the Third Reich was far from unblemished, they possessed enough semi-autonomous power to stand up to the state on key occasions. This was resistance only in a very qualified sense of the term, but it did create a postwar myth of Christian opposition to Hitler and state persecution. These Janus-faced memories of weakness and resistance became crucial as various Christian intellectuals and thinkers sought to recast German Christianity for the politics of Stunde Null (zero hour) in 1945.

While the Centre did reestablish itself as a party in North Rhine Westphalia, largely as a byproduct of the sponsorship of the British military government an adroit activism on the part of Carl Spiecker, the bulk of Centre veterans favored creating a new, umbrella Christian party that would be interdenominational. Many of the surviving Centre's leaders gravitated towards interdenominationalism in this period in what would later become the CDU. This was not just limited to the figure of Adenauer, but consisted of a whole panoply of Centre luminaries like Jakob Kaiser, Andreas Hermes, and Theodor Scharmitzel. Not only did the proto-CDU siphon off many of the Centre's leadership, but the process of party formation in the Western zones was largely organized by Catholic figures, some of whom were previously affiliated with the Centre. These activists helped laid the groundwork for licensing the CDU with the occupation governments and paved the way for the CDU to quickly become an umbrella party for very various Christian groups and individuals. This process of denuding the Centre of potential leadership and management talent limited any possibility of a resurgent Centre during the postwar, and the successes of the CDU on a national scale helped cement this process.

But the CDU was not really a stalking horse for a postwar Centre, even though its leadership and the tone of its politics was heavily Catholic. One of the reasons why the CDU's electoral program was so successful was that its meshed well with both preexisting trends in German political Catholicism and the experience of many German Christians both during the Third Reich as well as the immediate postwar years. Much of the CDU's leadership was predisposed to craft an interdenominational party on the basis of their previous experiences with the Centre. Kaiser and other CDU luminaries had memories of the Turm that ultimately proved counterproductive; while the Centre could accrue Catholic votes, it could not break out of its confessional base. Therefore, the Centre had to govern as a coalition partner, but its explicitly Catholic orientation hamstrung its ability to craft these political alliances. For Kaiser, this pattern of parochial politics was counterproductive for the wider goals of Christianity in Germany. In statements emanating from the Berlin executive, Kaiser would assert that the most important facet of the CDU was its acceptance of all German Christians. Although this acceptance of all German Christian denominations was selective in practice, it was powerful enough that it was able to appeal to mainstream German Protestants and attract figures like Eugen Kogon.

This form of interdenominational umbrella politics was quite powerful and attractive during the postwar milieu. One of the emerging meta-narratives for German Christians was that their principled resistance to Hitler and Nazism was undercut by Hitler's ability to isolate the churches and prevent them from working together. While there are a number of flaws and self-serving exculpatory simplifications in this narrative (as well as instances of genuine resistance- Kogon, for example, was imprisoned in Buchenwald), it reinforced the political idea that German Christianity had to rise above the squabbles of denomination to meet the challenges of the postwar order. In an appeal to the CDU in the Rhineland in November 1945, Karl Zimmermann ambitiously framed the CDU's mission:

A new page of history has turned, whose first lines speak of the necessity of union of the two Christian confessions in politics.

Zimmermann's claim of union contained both the historic sense of mission of the CDU -moving past the sixteenth-century Reformation- but also articulated a vision that a Christian form of politics would restore Germany's moral standing. This redemptive quality of religiously-infused politics found a wide degree of resonance among Catholics and Protestants alike. It simultaneously deflected charges of moral complicity in the crimes of the Third Reich by castigating the latter as fundamentally anti-Christian as well as orientating postwar politics against the rise of communism. The CDU's anticommunism acted as a unifying force for its pan-confessionalism and the actions of the Soviet zone's military government to control the CDU and the churches invited comparisons to Hitler's church policies.

This anticommunist glue unified a diverse set of thinkers and faiths, but the actual political agenda for the CDU was quite complex. FRG electoral politics meant that it had to respect the Catholic and Bavarian CSU's own autonomy in Bavaria. The domestic agenda of the CDU often respected the churches' autonomy and control over institutions like schooling or hospitals. In other areas, interconfessional solidarity was possible such as antiabortion legislation and moves against pornography and other materials damaging the moral fiber of the country built on overlapping consensus between the German churches. But other aspects of domestic policy were more difficult for the Chancellor to harmonize between politics and faith. Adenauer's social market economy melded aspects of ordoliberalism like Ludwig Erhard as well as various Christian thinkers' writings on the social economy was one of his solutions to this dilemma.