There are two aspects of this question that make it a tricky one to answer. Firstly, American politics has made the definition of liberal so incoherent that the term has actually lost much of its political definition. Generally speaking in US conservative news outlets like Fox News or social media, "liberal" is an epithet that can describe figures ranging from Al Gore to Noam Chomsky, ignoring the vast differences in ideology and positions of these people. This has divorced liberalism from its mid-twentieth-century historical meaning in the US which tended to equate it with left-of-center politics. Historians for example use the term "Cold War Liberalism" to describe the politics of Arthur Schlesinger, Jr. or JFK who tended to have a domestic policy of moderate government spending, progressive taxation, and pro-labor initiatives while maintaining a staunch anticommunist line internationally and giving a degree of tacit sanction to attempts to ferret out suspected communists while supporting a massive military build-up to meet the communist threat. But the term Liberal became much more plastic as time went on, especially in the political and cultural wars of the late 1960s and early 70s when it increasingly became a slur devoid of much actual meaning.

The other problem with the question is that liberal has specific political connotations in continental Europe. Unlike the US there were actual political parties that called themselves liberal and liberalism had a very long political heritage that stretched into the nineteenth century. Historians call Napoleon's government during the Hundred Days the Liberal Empire because he championed a constitution that in theory bound his power and courted noted former Revolutionaries like Benjamin Constant. Liberalism in the post-1815 period was generally an oppositional movement that pushed for either implementing a constitution or expanding existing ones.

Within the German states, liberals tended to cluster around various social milieus associated with opposition to monarchic authority and drew their ranks from the professionals in the glowing middle strata of society. German liberals tended to be partisans for national unification under a constitutional monarch and the Paulskirche parliament of the 1848 Revolution proposed such a thing to the Hohenzollern monarch, only to be refused. Even though defeated in 1848, German liberals remained a potent force within German politics through unification, when Bismarck co-opted elements of their platforms. German liberals in the empire tended to be a centrist political movement with some left liberals attacking the authoritarian Bismarckian system while right liberals supported German nationalism and overseas expansion. But unification proved to be something of a mixed blessing for German liberals as they were no longer the politics of the opposition. Both organized Catholicism in the form of the Centre Party and socialism in the SPD soon became the main opponents of the imperial state. Moreover, German liberalism found itself stretched in many different directions; not only did liberalism splinter in an age of mass politics, it also found its power in national politics slip considerably.

German liberalism was very much a declining political force by 1914. The war accelerated these trends as mass politics became more, for lack of a better word, mass, and the liberalism' political platform of constitutionalism, rule of law, and centrist politics seemed to be that of a more bygone prewar era. Although splintering continued apace in Weimar, German liberalism had two main political parties: the DDP which was more left-leaning and the DVP which was center-right. These parties tended to act as coalition partners as they could never reliably break over 10% of the vote for the Reichstag.

This wider trend of weakening political power defined much of German liberals' responses to the rise of Hitler, which ranged from disgust and rejection of the NSDAP to the cooption. Liberals within the more left-wing orientated DDP tended to place themselves in opposition to Hitler between 1929-33, but it is important to realize that German liberals were often not opposing Hitler per se, but rather a wider turn in German politics towards extremism both on the left and far-right. Yet German liberals were not above the wider radicalization process that transformed Weimar politics in the 1930s. Many of the DDP and DVP intellectuals embraced various völkisch ideas developed during the war, and often saw the rise of communism as a greater threat to Germany than Hitler's NSDAP. This ideological overlap with some of the tenets of National Socialism made it much more difficult for liberals to form political coalitions with either the SPD or Centre parties in opposition to Hitler and the various conservative political parties seeking to end the Republic.

The result was that the picture of liberals in Germany was either of a doomed rearguard against the rise of Hitler or a cowardly surrender to the Nazis. But liberals' responses to various Nazi political initiatives was often quite complex, and elides simple notions of last stands or surrender. The position of various liberals in the passage of Enabling Act in 1933 was emblematic of this multifacted response to the rise of the dictatorship. With one lone exception, all of the DStP (a successor of sorts to the DDP) delegates in the Reichstag voted for the Enabling Act, a seemingly about-face to liberal democratic principles. But the rationale for supporting the Enabling Act varied among the deputies. Some of the support was due to a deepening cynicism about the Republic and its institutions, and some liberals like Ernst Lemmer joined the NSDAP outright. Other liberals, especially those influenced by Friedrich Naumann's thinking, disliked the crudeness of the NSDAP's politics and leaders, but saw some virtue in its economic and social policies. Hjalmar Schacht was the most prominent liberal in this category, seeing in dictatorial powers the key to restructuring the economy. Still other liberals saw the Enabling Act as the least-worst alternative between an Unrechtsstaat (lawless state) and a restricted Rechtsstaat (state defined by laws). By sanctioning the Act, the state was still acknowledging the importance of German law and jurisprudence instead of proceeding without the sanction of law. Finally, other liberals saw their affirmative vote as a tactical move that preserved their continued opposition to Hitler. A number of liberal recognized that the Act had enough support to pass, but also that Hitler was not above using extralegal means if thwarted. Therefore, it was important not to give Hitler a pretext to further clamp down on liberal politicians and intellectual circles. As the liberal leader Hermann Dietrich explained in a letter to a colleague angered by the vote:

after it was certain that all the bourgeois parties would vote for the Enabling Act, it became difficult for our representatives to do otherwise if they did not want to stand in opposition with the SPD. That would have had the same consequence that we would have been placed in the same camp as the Marxists, and it would have made it easier for government to take measures against us. It was also necessary, moreover, to take into consideration democratic officials, who have a difficult enough struggle already. Here again we had to support measures we privately opposed. This can no longer be avoided under the present circumstances.

In hindsight, this type of accommodation politics proved to be quite disastrous and only entrenched the dictatorship. Schacht, for example, was sidelined in the Economics ministry after his opposition to rearmament found little support in the Chancellery and far from reining in the NSDAP's reliance upon extralegal methods, the Enabling Act only encouraged these methods.