Revanchism (from French revanche, "revenge") is a term used since the 1870s to describe political campaigns to reverse territorial losses incurred by a country during previous wars and strifes, sometimes quite distant in time. Revanchism draws strength from desires to regain national esteem, local geo-political dominance, or economic advantages by subduing a foe. Extreme revanchist ideologues often represent a pro-war stance, suggesting that the losses can be reclaimed only through a new war.

Revanchist politics often rely on the identification of a nation with a nation-state, often mobilizing deep-rooted sentiments of ethnic nationalism, claiming territories outside of the state where members of the nation live, and use heavy-handed chauvinist nationalism to mobilise support for their aims. Revanchist justifications are often presented as based on ancient, or even autochthonous occupation of a territory, known as Urrecht .

Motivations of territorial aggression and counter aggression are as old as tribal societies, but the instance of modern revanchism that gave these furious groundswells of opinion their modern name lie in the strong desire by right-wingers in the French Third Republic to regain Alsace and Lorraine after the humiliating defeat in the Franco-Prussian War in 1871. This ultra-nationalist tradition influenced French politics up to 1921. This is one of the major reasons France went to great pains to woo Russia over to its side, first by means of the Franco-Russian Alliance of 1894, and then by a series of accords, including the Triple Entente, which eventually led Russia to enter World War I on the side of the Allies.

Revanchist sentiments provoked two 19th-century wars between Prussia and Denmark over Schleswig and Holstein (the First war of Schleswig 1848-1851 and the Second war of Schleswig in 1864).

Another notable revanchist movement was that of the right-wing nationalists in the German Weimar Republic for the reconquest of Danzig, Posen and sometimes Alsace-Lorraine, the Sudetenland and other territories considered to be "rightfully" the property of the German nation. Similar sentiments prevailed in post-WW1 Hungary, which called for a revision of the borders set up by the Treaty of Trianon, especially with Romania.

Modern revanchist politics center around certain areas of historic competition, such as Carpathian Ruthenia and Israel/Palestine.

See also

• Irredentism
• Reconquista