In this monumental and provocative history, Patrick Buchanan makes the case that, if not for the blunders of British statesmen- Winston Churchill first among them-the horrors of two world wars and the Holocaust might have been avoided and the British Empire might never have collapsed into ruins. Half a century of murderous oppression of scores of millions under the iron boot of Communist tyranny might never have happened, and Europe's central role in world affairs might have been sustained for many generations.

Among the British and Churchillian errors were:
- The secret decision of a tiny cabal in the inner Cabinet in 1906 to take Britain straight to war against Germany, should she invade France
- The vengeful Treaty of Versailles that mutilated Germany, leaving her bitter, betrayed, and receptive to the appeal of Adolf Hitler
- Britain's capitulation, at Churchill's urging, to American pressure to sever the Anglo-Japanese alliance, insulting and isolating Japan, pushing her onto the path of militarism and conquest
- The greatest mistake in British history: the unsolicited war guarantee to Poland of March 1939, ensuring the Second World War

Certain to create controversy and spirited argument, Churchill, Hitler, and "the Unnecessary War" is a grand and bold insight into the historic failures of judgment that ended centuries of European rule and guaranteed a future no one who lived in that vanished world could ever have envisioned.