The Long War was fought between the Habsburgs and the Ottoman Empire from 1590 to 1606.

The Long War is also a name proposed by Philip Bobbitt in The Shield of Achilles: War, Peace and the Course of History, to describe the series of major conflicts fought from the start of the First World War in 1914 to the decline of the Soviet Union in 1990.

The Long War, as proposed by Bobbitt, includes the First World War, the Second World War, the Korean War, the Vietnam War, as well as the Bolshevik Revolution, the Chinese Civil War, the Spanish Civil War and the Cold War. These wars were all fought over a single set of constitutional issues, to determine which form of constitution – liberal democracy, fascism or communism – would replace the colonial ideology of the imperial states of Europe that had emerged after the epochal Napoleonic Wars that had dominated the world between the Congress of Vienna and August 1914. Just as earlier epochal wars were resolved by major international settlements, - Westphalia, Utrecht and Vienna – so the Long War was resolved by the 1990 Charter of Paris for a New Europe .

The Long War follows a view of history understood as a series of epochal wars that have shaped both state consititutions and international relations. Bobbitt traces this perspective of military history via Hobbes and Machiavelli to Thucydides. The Greek historian Thucydides, for example, identified the wars of the fifth century BC in the Hellenic world as a constitutional struggle between the hegemons Athens and Sparta, which he called the Peloponnesian War.