Twentieth-century antisemitism is usually attributed to one of two main causes: theological antipathy or racial prejudice. Recent Catholic apologetic has claimed that the former motive was largely superseded by the latter, particularly during the horrendous years of persecution and mass murder perpetrated by the Nazis. But Ulrike Ehret, in her thoroughly researched dissertation comparing German and English Catholic attitudes, comes to the conclusion that religion and modern anti-Jewish prejudices cannot be so easily separated from each other. She also finds that the socio-cultural and national-political mindsets amongst Catholics fostered antisemitic attitudes in both countries, though with differing intensities and at different times. Catholics in both England and Germany were a minority, and their leaders shared similar worldviews, upholding a traditional order of established values under the authority of a God-given ruler. But the disasters, both personal and national, of the First World War overthrew such beliefs. Instead Catholics were confronted with defeat, revolution and economic turmoil. In their search for scapegoats it was easy to focus on those alien elements that apparently had caused such disasters. Catholic publications early on saw the Jewish-Bolshevik threat as endangering their Christian civilisation. They often extended this polemic into suitably extreme conspiracy theories. Such staunchly nationalistic and anti-Communist views led most German Catholics to support Hitler, and to welcome the Concordat reached in 1933 between the Nazi government and the Vatican. In England, such feelings gave opportunity to such successful Catholic writers as Hilaire Belloc and G. K. Chesterton to find a ready audience for their conservative and often antisemitic sentiments.

It was this climate of fearful opinion, rather than religious intolerance, or proto-fascist sympathies, which Ehret suggests was predominant among both sets of Catholics. German Catholic support for the Nazi regime precluded them from any open objections to its racist ideology. Only too late did the Catholic leaders begin to recognise that the same fanaticism would be launched against their Church. So too, in England, Catholic sympathies were voiced in support of Franco's attempt to root out Jewish Bolshevism in Spain. Not until 1938 did the English Catholic hierarchy change its tune and begin to urge support for the Nazis' victims, though principally for Jews who had converted to Catholicism.

For too long the Catholic stereotypes about Jewish Bolshevism or the so-called Jewish question were upheld in defence of the equally mythical Christian nature of British or German society. Such attitudes prevented any timely measures to counter the rising tide of Nazi persecution. More particularly they prevented the growth amongst Catholics of any more tolerant acceptance of Judaism or Jews as they really were. Only in the aftermath of the Holocaust did Catholics begin to abandon these long-held mythologies. Ehret's valuable analysis of the various strands of anti-Jewish sentiment stands as a warning against this conflation and misuse of religious imagery for political and social purposes.

Probst covers much the same ground, but solely from the perspective of German Protestants. He seeks to trace the baneful influence of the misuse of Luther's legacy amongst these church members. His carefully situated case studies show that a significant number of pastors, bishops and theologians made use of Luther's writings about Jews and Judaism to reinforce the existing Christian anti-Judaism amongst German Protestants. At the same time Probst also challenges the dichotomy between theological anti-Judaism and racial antisemitism, since he sees a great deal of overlap both in the sixteenth as well as the twentieth century. Anti-Judaism and antisemitism existed side-by-side in both Luther's writings and in those of many German Protestants in the Nazi era.

There can be no doubt that a sizeable and vocal minority of church members avidly and openly supported the Nazis' virulent opposition to the Jews. Their sermons and speeches were redolent with Christian anti-Judaism backed by nationalistic overtones. The question is how far these attitudes can be attributed to Luther's influence. Probst affirms that German Protestant responses to Luther's antisemitic writings have not been examined before, and warns against any simplistic causal relationship to the horrors of the Holocaust. But, in fact, it was this negative conditioning over centuries that was responsible for the total absence of any pro-Jewish sentiments, even for those Jewish converts who belonged to Protestant congregations. On the other hand, the most vociferous Protestant preachers voicing antisemitic sentiments belonged to the so-called German Christians, whose devotion to the Nazi cause was unbounded. But, as Doris Bergen has amply shown, these men were politically-motivated opportunists who rode the Nazi bandwagon and used its rhetoric to advance their own careers. They were also woefully weak in theology, even contemptuous of Christianity's historic roots, or even claimed that Jesus was not a Jew. Their use of Luther was palpably tactical, showed a decided lack of nuance, and was certainly not the result of deep scholarly enquiry. For example, the excesses of the so-called Kristallnacht in 1938 were justified by appropriate quotations from Luther's inflammatory diatribes. Even in the case of those theologians who wrote explicitly about Luther's antisemitic writings – Probst skilfully examines several of these – their conclusions predictably buttressed their pre-existing prejudices.

More ambivalent were the theologians of the Confessing Church who sought to rescue Luther and Christianity – but not their Jewish neighbours – from the Nazis. Their defensive struggle from 1934 onwards was preoccupied with the fight to defend the Church's doctrines and autonomy from both Nazi radicalism and German Christian distortions of the Gospel. Some of these pastors ran into serious trouble from Nazi radicals for baptising Jews willing to convert. Others justified the practice by citing Luther's instructions. But they too shared the current antipathy to the unconverted Jews. Their passivity and silence in face of the escalating Nazi violence against the Jews of Europe has been rightly condemned by all later commentators, including Probst. But the extent to which Luther can be held responsible for this demonising of the Jew remains an open question. Probst successfully argues that Luther's incendiary language was useful as ammunition to support the cause. But his evidence seems to show that Protestant beliefs in German national superiority, their strident opposition to Bolshevism, and their widespread accommodation to the Nazis' racial goals, were more potent factors. Above all, Luther's failure to take a stand in favour of Jews and Judaism was to prove a lasting and ill-omened legacy.