Hussein Onyango Obama is unusual among Churchill’s victims only in one respect: his story has been rescued from the slipstream of history. Churchill believed the highlands, the most fertile land in Kenya, should be the sole preserve of the white settlers, and approved of the clearing out of the local “kaffirs.” When the Kikuyu rebelled under Churchill’s postwar premiership, some 150,000 of them were forced at gunpoint into detention camps, later called “Britain’s gulag” by the historian Caroline Elkins. Obama never truly recovered from the torture he endured.

This is a real Churchill, and a dark one — but it is not the only Churchill. He also saw the Nazi threat far ahead of the complacent British establishment, and his extraordinary leadership may have been the decisive factor in vanquishing Hitlerism from Europe. Toye is no Nicholson Baker, the appalling pseudo­historian whose recent work “Human Smoke” presented Churchill as no different from Hitler. Toye sees all this, clearly and emphatically.

So how can the two Churchills be reconciled? Was his moral opposition to Nazism a charade, masking the fact that he was merely trying to defend the British Empire from a rival? Toye quotes Richard B. Moore, an American civil rights leader, who said that it was “a most rare and fortunate coincidence” that at that moment “the vital interests of the British Empire” coincided “with those of the great overwhelming majority of mankind.” But this might be too soft in its praise. If Churchill had been interested only in saving the empire, he could probably have cut a deal with Hitler. No: he had a deeper repugnance to Nazism than that. He may have been a thug, but he knew a greater thug when he saw one — and we may owe our freedom today to this wrinkle in history.

This is the great, enduring paradox of Churchill’s life. In leading the charge against Nazism, he produced some of the richest prose poetry in defense of freedom and democracy ever written. It was a check he didn’t want black or Asian people to cash, but as the Ghanaian nationalist Kwame Nkrumah wrote, “all the fair brave words spoken about freedom that had been broadcast to the four corners of the earth took seed and grew where they had not been intended.” Churchill lived to see democrats across Britain’s imperial conquests use his own hope-songs of freedom against him.

In the end, the words of the great and glorious Churchill who resisted dictatorship overwhelmed the works of the cruel and cramped Churchill who tried to impose it on the world’s people of color. Toye teases out these ambiguities beautifully. The fact that we now live at a time where a free and independent India is an emerging superpower in the process of eclipsing Britain, and a grandson of the Kikuyu “savages” is the most powerful man in the world, is a repudiation of Churchill at his ugliest — and a sweet, unsought victory for Churchill at his best.