Carl Schmitt was a German legal philosopher and political theorist, a critic of democracy and liberalism, and a rabid antisemite who served as the chief legal adviser to the Nazis and the Third Reich. One of his main arguments was that a leader ("the sovereign") who has been given legitimacy and power by the people (preferably "homogenous") can decide to create a "state of exception" in response to some type of "crisis". In essence, a leader can use the law (or work outside of it) as he sees fit in the interest of the public good — as he defines it. Schmitt also believed that violence was the basic essence of politics and power, and that political decision-making should be structured by the distinction between friend and enemy (meaning the Other).
For obvious reasons, Schmitt's theories about a state of exception, violence, totalitarianism, and nationalism were highly appealing for the Nazis and other such antidemocratic and illiberal movements and leaders.
