The concept of defensive or fighting democracy developed during the Interwar period in the shadow of the rise of fascist regimes. Its primary proponent, Karl Loewenstein, drew from his own experiences in Nazi Germany. Through his writings, he highlighted how fascist parties and movements utilized the means provided by democratic constitutional institutions to establish their position and infiltrate both the electorate and representative bodies like a Trojan Horse.

At the same time, he emphasized that democracies can only survive if they understand that they must defend themselves against their enemies, both external and internal.

Loewenstein's final conclusion is that democracy must defend its institutions. His analyses of the methods extremists use to influence the electorate—employing emotions (anger, frustration, dissatisfaction, complexes) and exploiting democratic institutions—are not only timely but also extremely useful in countering enemies of democracy.