We tend to think that imperialism is motivated by greed and racism, but it’s just as often inspired by altruism. From Rudyard Kipling urging colonization of the Philippines to Christopher Hitchens urging regime change in Iraq, humanitarian concerns make for foreign adventures. In case after case, empathy turns out to be another word for invasion.

Of course, many would say that empires use ideals cynically, to cover their tracks. They might assert, for example, that presidential talk about democracy is nothing more than a ploy designed to conceal the thirst for oil—altruism becomes a kind of conspiracy. It’s this notion that Richard Huzzey meticulously dismantles in his new book, Freedom Burning: Anti-Slavery and Empire in Victorian Britain (Cornell University Press).

Freedom Burning focuses on British antislavery sentiment in the years after 1833, when the government of King William IV essentially outlawed slavery throughout the empire. The topic is fascinating, and certainly relevant to our own imperial moment.But Huzzey, an English academic, isn’t an especially engaging writer. His book is a dry read, laboriously wending its way through a maze of Foreign Office policy, parliamentary politics, and dead controversies. Huzzey often seems to go out of his way to avoid telling a good story. Case in point: he repeatedly refers to the British Niger expedition of 1841, an antislavery-inspired disaster in which more than a third of the 159 European participants died, but eschews every opportunity to give us even the outlines of what happened.

Huzzey’s bland delivery is useful, though, in that it puts into relief the bitterness of his conclusion. Antislavery dogma wasn’t a fig leaf for British imperialism, he argues, but one of its engines, driving the consensus that made expansion possible. British determination to search all shipping on the high seas was motivated in large part by the desire to prevent the transportation of slaves. The Victorians who torched a West African settlement in 1845 saw themselves as being allied with its inhabitants, whose leaders had allegedly dealt with slave traders. Anticipating America’s approach in Vietnam, they were literally destroying the village in order to save it.

Antislavery principles became not an excuse but a motive for the exercise of British power. “[A]nti-slavery was the popular aspect of imperial expansion,” Huzzey says, and “one of the principal ways that commercial, spiritual, and moral objectives could be combined.” Like their constituents, British politicians thought about foreign policy against the backdrop of tenets to which virtually everyone subscribed. It was just about impossible, Huzzey notes, “to be taken seriously in public debates if an author defended slavery.” Thus, when some Brits argued against the naval suppression of the slave trade, they did so on the premise that it would force the trade underground, which might worsen conditions for transported slaves and even cause slavers to throw their cargo overboard at the approach of a British ship.

Antislavery ideology was adaptable enough to exist alongside open and vicious racism. Indeed, as Huzzey points out, it even provided white Britons with a strong rationale for hating their black countrymen. The prevalence of slavery in Africa and the complicity of African leaders in the slave trade were taken as proofs of black racial inferiority and immorality.

Still more damaging was the confluence of antislavery convictions and racism in the West Indies. There, freed black British slaves were reluctant to return to the plantation system, preferring instead to work for themselves. To white Brits, that indicated laziness and backwardness, which solidified racial stereotypes. Even the antislavery argument that bondage was dehumanizing got turned against the freedmen: if they were dehumanized, the reasoning went, then they shouldn’t be treated as human. And so antislavery convictions provided the foundation for coercive laws forcing former slaves back onto the plantations.

The belief in freedom, then, didn’t lead to a belief in equality. On the contrary, it ended up justifying inequity—and, arguably, encouraging a different form of servitude. Even as the British were boarding the ships of other nations in search of slaves, their own vessels carried hundreds of thousands of East Indian laborers across the empire. These Indians were not technically slaves but indentured servants, obliged to work under debt bondage or contract. Though there was some outcry against their treatment, the Indians’ situation wasn’t necessarily seen as incompatible with an antislavery stance. Rather, inasmuch as ex-slaves were considered undependable, it was thought that some form of forced labor was required to secure a stable postslavery economy.

One of the main contributions the antislavery movement made to imperialism may have been simple awareness. “The suppression of the slave trade provided much early interest in Africa,” Huzzey writes, “where otherwise there would have been little or none.” Britain had been imperialistic long before the 19th century, of course, but its ambitions hadn’t been aimed in this particular direction. The same moral energy that powered abolition flowed naturally, once that was accomplished, into meddling in Africa, with devastating consequences.

Did those consequences negate the benefits of abolition? Would an earlier end to slavery have triggered an even more thorough and rapacious imperial presence in Africa? And conversely, if slavery had been allowed to continue—say, until after the American Civil War—would Africa have suffered a shorter, less crippling colonization?

Huzzey raises these questions but is too careful to offer answers. Nevertheless, I wish every do-gooder, left, right, and center, would read his book—and not just because it might briefly distract them from their violent schemes for world betterment. Freedom Burning suggests not just that the road to hell is paved with good intentions, but, more specifically, that it’s paved with our good intentions. Freedom, democracy, empathy, even equality—America’s ideals are weapons of mass destruction waiting to be armed and detonated wherever our attention happens to alight, whether it’s Africa, Kosovo, or Iraq. Our humanitarian efforts are laudable and do enormous good throughout the world. But it’s hard to read this book without wondering whether it might not be better for suffering humanity if we cared about them a little less and minded our own business a little more.