UNLIKE WARS, MANHUNTS promise a sort of tidiness. They begin and end with images — a charcoal sketch or youthful mugshot — and end with grizzled defeat or something gorier, confirmation that the good guys won. Two of the most important manhunts of the last decade have been far from tidy because they became confused with, interrupted by, or subsumed in what was called the War on Terror. The signature crime of both men forced a realization that terrorists could wreak enough destruction, even on American soil, long defended by the world’s best army and protected by its biggest oceans, to be on par with an enemy state. Rather than hunt Osama bin Laden and Khalid Sheikh Mohammed outright with law enforcement, the United States declared war.

For years after 9/11, no one even knew Khalid Sheikh Mohammed — the architect of the World Trade Center attack, the grand strategist of terrorism, “the ghost of our times,” in the words of Terry McDermott and Josh Meyer — was wanted. When Mohammed was finally imagined, named, sought, and captured, the conclusive and famous photograph of him was staged not in standard mugshot format, but in a mode clearly meant to shame. The man who had evaded the technology and intelligence of the most powerful country in the world had to be made to look down and out. A CIA agent mussed his hair, put him in an ugly t-shirt with a loose neck, and caught him making a haggard grimace.

Unlike Mohammed, Osama bin Laden’s photograph was everywhere, in large part because the terrorist himself, rather than his hunters, encouraged its proliferation. George W. Bush evoked the paradigmatic era of manhunts — the Old West, with newborn American law extending bravely into lawless lands — and said he wanted Osama, dead or alive. You could hear the Bon Jovi and see the sepia-toned poster (the New York Post mocked one up). When Barack Obama caught Bin Laden, realizing that “alive” wasn’t prudent, his administration botched the final photograph. Then-CIA head Leon Panetta promised it; the White House retreated; faked photos of Bin Laden, brains blown out, eyeball exploded, substituted.

Wars and manhunts have been confused before, in that other open-ended conflict, the War on Drugs (which itself has mixed up with the War on Terror in poppy-growing Afghanistan to disastrous results). But for decades, from 1960s leftist protestors to the lonely white male bombers of the 1990s, American law enforcement answered terrorism with manhunts, led by the Federal Bureau of Investigation and prosecuted in civilian courts. The goals of manhunts were always evidence, verdicts, and inmates. The goals of war, alternately, were intelligence, victory, and bodies. Since the start of the war on terror, its supporters on the left and right have argued that the old way of handling terrorism is ineffective and even dangerous: evidence exposes intelligence; verdicts threaten victory; inmates demand habeas corpus. (Bodies make no demands but they do anger allies and enemies alike.)

Books on Mohammed, by McDermott and Meyer, and on Bin Laden, by Peter Bergen, are titled and framed according to the manhunt. They are as tightly told as a Western, starting with the beginning of the hunt, introducing the pursuers, men and women no one would want on their trail, detailing their daring tactics, and ending with a captured man. But even though they end with their men, with a largely vanquished Al Qaeda, with a waning Iraq war and a waxing Arab Spring, b...