Carl Schmitt's early career as an academic lawyer falls into the last years of the Wilhelmine Empire. (See for Schmitt's life and career: Bendersky 1983; Balakrishnan 2000; Mehring 2009.) But Schmitt wrote his most influential works, as a young professor of constitutional law in Bonn and later in Berlin, during the Weimar-period: Political Theology, presenting Schmitt's theory of sovereignty, appeared in 1922, to be followed in 1923 by The Crisis of Parliamentary Democracy, which attacked the legitimacy of parliamentary government. In 1927, Schmitt published the first version of his most famous work, The Concept of the Political, defending the view that all true politics is based on the distinction between friend and enemy. The culmination of Schmitt's work in the Weimar period, and arguably his greatest achievement, is the 1928 Constitutional Theory which systematically applied Schmitt's political theory to the interpretation of the Weimar constitution. During the political and constitutional crisis of the later Weimar Republic Schmitt published Legality and Legitimacy, a clear-sighted analysis of the breakdown of parliamentary government Germany, as well as The Guardian of the Constitution, which argued that the president as the head of the executive, and not a constitutional court, ought to be recognized as the guardian of the constitution. In these works from the later Weimar period, Schmitt's declared aim to defend the Weimar constitution is at times barely distinguishable from a call for constitutional revision towards a more authoritarian political framework (Dyzenhaus 1997, 70–85; Kennedy 2004, 154–78).
Though Schmitt had not been a supporter of National Socialism before Hitler came to power, he sided with the Nazis after 1933. Schmitt quickly obtained an influential position in the legal profession and came to be perceived as the ‘Crown Jurist’ of National Socialism. (Rüthers 1990; Mehring 2009, 304–436) He devoted himself, with undue enthusiasm, to such tasks as the defence of Hitler's extra-judicial killings of political opponents (PB 227–32) and the purging of German jurisprudence of Jewish influence (Gross 2007; Mehring 2009, 358–80). But Schmitt was ousted from his position of power within legal academia in 1936, after infighting with academic competitors who viewed Schmitt as a turncoat who had converted to Nazism only to advance his career. There is considerable debate about the causes of Schmitt's willingness to associate himself with the Nazis. Some authors point to Schmitt's strong ambition and his opportunistic character but deny ideological affinity (Bendersky 1983, 195–242; Schwab 1989). But a strong case has been made that Schmitt's anti-liberal jurisprudence, as well as his fervent anti-semitism, disposed him to support the Nazi regime (Dyzenhaus 1997, 85–101; Scheuerman 1999). Throughout the later Nazi period, Schmitt's work focused on questions of international law. The immediate motivation for this turn seems to have been the aim to justify Nazi-expansionism. But Schmitt was interested in the wider question of the foundations of international law, and he was convinced that the turn towards liberal cosmopolitanism in 20th century international law would undermine the conditions of stable and legitimate international legal order. Schmitt's theoretical work on the foundations of international law culminated in The Nomos of the Earth, written in the early 1940's, but not published before 1950. Due to his support for and involvement with the Nazi dictatorship, the obstinately unrepentant Schmitt was not allowed to return to an academic job after 1945 (Mehring 2009, 438–63). But he nevertheless remained an important figure in West Germany's conservative intellectual scene to his death in 1985 (van Laak 2002) and enjoyed a considerable degree of clandestine influence elsewhere (Scheuerman 1999, 183–251; Müller 2003).
Unsurprisingly, the significance and value of Schmitt's works