We must never forget that the record of the 20th century is one of appalling human tragedy, much of it caused by the clash of ideologies.
Analysis
The 20th century saw major ideological clashes (e.g., fascism vs. communism vs. democracy) leading to catastrophic events like World War II, the Holocaust, and the Cold War. Historians widely agree these conflicts caused unprecedented human suffering. Blair's phrasing aligns with this established historical narrative.
Background
The 20th century was marked by ideological struggles, including colonialism, totalitarian regimes, and superpower rivalries, resulting in wars, genocides, and political repression. Scholars estimate these conflicts caused tens of millions of deaths.
Verdict summary
Blair's statement accurately reflects the widespread historical consensus on the 20th century's ideological conflicts and their human cost.
Sources consulted
— Hobsbawm, Eric. *The Age of Extremes: The Short Twentieth Century, 1914–1991* (1994).
— Judt, Tony. *Postwar: A History of Europe Since 1945* (2005).
— United Nations. *The Human Cost of War* (2000).