By John le Carré

Viking Press, $28.95; 310 pp.

Intelligence analysts, police detectives, journalists, and historians are all inquirers of the past: they come upon an event and must reconstruct its origins. While serving in Great Britain’s intelligence services, MI5 and MI6, David John Moore Cornwell acquired this perspective of playwright in reverse for the novels he has written under the name John le Carré. His 23rd and latest, A Delicate Truth, explores how the global war on terror spawns Operation Wildfire and its attendant collateral damage.

Fergus Quinn is a British politician on the make, appointed Minister of State to the Foreign Office. He is “vocal, belligerent,” full of “privileged discontent” and easy target for Jay Crispin, a “contractor,” who would privatize counterterrorism through an alliance with the American mercenaries from Ethical Outcomes Incorporated. The proprietary intelligence Crispin proffers is at least as good as the intelligence that promised weapons of mass destruction in Iraq — meaning that right or wrong, it is irresistibly enticing.

A Polish arms dealer, code named Aladdin, is to make contact with a Jihadi terrorist, code named Punter, in the British possession of Gibraltar, to transfer hand-held, surface-to-air missiles capable of destroying commercial aircraft. British Special Forces from land and American mercenaries from sea will trap Punter with the weapons, fame and fortune to follow.Quinn’s reservations overcome by ambition and inexperience, he agrees, but without official sanction must tell no one in his office, above all not Private Secretary Tobius Bell, must not be present at Gibraltar himself, and so sends a mediocre diplomat, Christopher Probyn, as his eyes and ears.

When the intelligence is wrong and the Americans are trigger-happy, an innocent woman and child are killed. Too far away to see, Probyn is told the operation is a grand success. Witnesses to the shooting, the four British soldiers are sworn under the Official Secrets Act.

Shocked but quick to seek refuge, Quinn quietly withdraws from politics to a position in the private business world.

Three years later, the secret is at risk because Jeb Owen, leader of the Special Forces group, is wracked with guilt, because Probyn suspects his rapid dispatch to the Caribbean as High Commissioner and then award of knighthood are hardly congruent with the rest of his career, and because Bell remembers back then that his mentor in the Diplomatic Service, Giles Oakley, warned him, “Whatever they’re plotting, Toby, you’re not to join in” and then later enjoined, “I’m telling you with all the emphasis at my command, that there’s nothing for you to know. There was nothing for you to know, and there will never be anything to know.”

Because it is profoundly dangerous to know — Owen, Probyn and Bell will discover so.

In his grand trilogy The Quest for Karla (1974-79), written at the height of the Cold War, le Carré had his favorite spy, George Smiley, insist that the West must be “inhuman in defense of our humanity.” Smiley himself was decent and compassionate but accepted the compromise of his integrity to defeat KGB/Moscow Centre opponents.

More than a decade later when le Carré wrote The Secret Pilgrim (1990), the Communist empire was close to collapse, and he had one of Smiley’s protégés wonder, “You want to say, ‘I slew the dragon, I left the world a safer place.’ You can’t really, not these days. Perhaps you never could.”

Writer by craft but moralist at heart, le Carré is ever raising essential questions about ends, means and justifications. These matters are inherently ambiguous, and in A Delicate Truth he has Oakley quote the 17th-century aphorist François de La Rochefoucauld, “Hypocrisy is the tribute vice pays to virtue.” Was La Rochefoucauld — is Oakley — praising hypocrisy or virtue? Bell has no hesitations: “What the gods and all reasonable humans fought in vain … was sheer bloody indifference to anybody’s interest but their own.”

About this particular slaying of dragons, Bell is speaking for le Carré.

Benjamin Franklin Martin is the Price Professor of History at LSU. His most recent book is Years of Plenty, Years of Want: France and the Legacy of the Great War (2013).