David Ignatius is a columnist for The Washington Post and the author of ten novels, most recently “The Quantum Spy.”

‘Events, dear boy, events.” In his masterful diplomatic memoir, William J. Burns uses this aphorism, attributed to former British prime minister Harold Macmillan, to explain what so often sabotaged the strategic plans of the five presidents he served.

These presidents all wanted to play a visionary “long game.” But as Burns cautions, “It’s the short game — coping with stuff that happens unexpectedly — that preoccupies policymakers and often shapes their legacies.” That has been especially true with the Middle East, bungled by one president after another, with the best of intentions. The region, he writes, “remained best in class in dysfunction and fragility.”

Burns has written a wise, sometimes rueful account of why things often don’t work out the way statesmen plan. Reading the book, you’ll appreciate why he is widely viewed as the best Foreign Service officer of his generation. His clarity, good judgment and basic decency come through on every page. Yet it’s painful that Burns, the best and brightest, couldn’t prevent the chain of error that helped undo the American century.

This book is fascinating in part for its account of how Burns became such a good diplomat. From the first, he was a golden boy, a young man whom older men and women instinctively trusted and cultivated. In his early years, he moved from mentor to mentor — from Colin Powell at the National Security Council to Dick Murphy at the Near East Bureau to Secretary of State Jim Baker. Burns doesn’t say so directly, but the reader senses that of all these teachers, the stealthy, subtly manipulative Baker may have been his favorite.

Burns was a listener, with fluent Arabic and Russian, and he could hear the nuances that others often missed. He worried about squeezing a wounded post-Soviet Russia too hard by over-aggressive expansion of NATO; he knew that toppling Saddam Hussein could destabilize Iraq and the Middle East; he sensed that overthrowing Hosni Mubarak might similarly create chaos in Egypt. But knowing and doing are different, unfortunately.

Reading Burns’s narrative of the cables and memoranda he sent to his superiors, I had two conclusions: First, he was usually correct in his intuitions about potential mistakes that presidents should avoid. But second, he usually went along with decisions, even when he sensed they could cause difficulty. The reader is left feeling grateful that Burns never resigned in protest but wondering if perhaps he should have.

President George W. Bush’s invasion of Iraq in 2003 is a prime example. Burns wrote a warning memo titled “The Perfect Storm” as an “antidote to the recklessly rosy assumptions” of the Bush administration. “We highlighted the deep sectarian fault lines in Iraq. . . . We emphasized the dangers of civil unrest and looting if the Iraqi military and security institutions collapsed. . . . We noted the likelihood that . . . Iran could wind up as a major beneficiary.”

Yet as Burns honestly admits, that wasn’t enough: “What we did not do . . . was take a hard stand against war altogether. . . . In the end, we pulled some punches. . . . Why didn’t I go to the mat in my opposition or quit? . . . I still find my own answer garbled and unsatisfying.” (For what it’s worth, I would make a similar self-criticism of my journalism during that period.)

Russia is another car wreck that Burns saw coming but couldn’t stop. He was a political officer in Moscow from 1994 to 1996, during the catastrophic disarray of Boris Yeltsin’s reign, when Russia was literally falling apart, and he returned as ambassador from 2005 to 2008, when Vladimir Putin was consolidating power and taking revenge. “Basically, we’re facing a Russia that’s too big a player on too many issues to ignore,” he wrote in a gloomy cable about Putin’s revanchism.

Burns had cautioned in a 1994 cable from Moscow that Russian hostility to NATO expansion “is almost universally felt across the political spectrum here,” but the United States went ahead anyway, admitting Poland, Hungary and the Czech Republic in 1999 and then moving further east. He quotes (without disagreement) George F. Kennan’s comment that this hyper-fast expansion of NATO was “the most fateful error of American policy in the entire post-Cold War era.”

By the time he returned to Moscow and presented his credentials at the Kremlin as ambassador in 2005, Putin pulled him aside and told him: “You Americans need to listen more. You can’t have everything your way anymore. We can have effective relations, but not just on your terms.”

Burns understood that the pugnacious Putin was looking for a fight, especially after Secretary of State Hillary Clinton challenged the legitimacy of his party’s success in the Duma elections in 2011 — which Putin would later cite as justification for his meddling against Clinton in the 2016 U.S. presidential election.

Yet for all his caution and good sense, Burns helped pull the tiger’s tail harder when he visited newly installed Ambassador Michael McFaul in January 2012 and accompanied him to meet Russian opposition leaders before the March presidential election. Putin saw it as more U.S. meddling, and the incident poisoned McFaul’s tenure in Moscow. “The nastiness never stopped,” Burns writes. “I just wish I hadn’t provided such an immediate and visible trigger.”

On Syria, Burns is brutally frank: “It is hard not to see Syria’s agony as an American policy failure.” As Obama’s deputy secretary of state, Burns advocated what I think were the right positions, arguing for an early push in 2012 to arm and train the Syrian opposition when it might have succeeded, and urging Obama to retaliate after President Bashar al-Assad violated global norms and used chemical weapons. He lost those fights but stayed on as deputy secretary.

Burns writes wisely of the Syria fiasco: “Yet again, where we ran into trouble was in our short game. We misaligned ends and means, promising too much, on the one hand — declaring that ‘Assad must go’ and setting ‘red lines’ — and applying tactical tools too grudgingly and incrementally, on the other.”

That’s the poignancy of Burns’s book: It illustrates the gap between knowing the right thing and getting it done.

A genuinely masterful example of how the policy process should work is the Iran nuclear negotiation, which Burns conducted through a “back channel” that amazingly remained a secret through eight rounds. I had to smile reading Burns’s frustration with the Iranians’ assertion of a “right to enrich” uranium, a claim they said had been bolstered by secret talks with “various Americans, including members of Congress.”

Burns doesn’t mention that the chief culprit in feeding Iran’s belief that the United States had conceded this “right” was John Kerry, who had the first exploratory talks in Oman when he was a senator, and later, of course, became Burns’s boss as secretary of state. (Kerry outed himself on the right-to-enrich issue in his own memoir, but Burns doesn’t rub it in.)

Burns closes with what I found a too-cheery reassurance about American “resilience” and the “plenty of reasons to be optimistic about the potential of American diplomacy.” I’d like to think he’s right, but the evidence is questionable.

The American-led global order is like a bridge that had weakened over decades and that finally cracked under the strain of President Trump’s disastrous leadership. The State Department and the National Security Council staff are gutted; American alliances are in disarray. Today, it’s fair to say the interagency policy process that Burns served for 31 years has all but collapsed.

A future president may repair some of the damage. But I’m not sure America will ever get back to where it was before November 2016, or March 2003, or Sept. 11, 2001 — pick your date when the yarn began to break. Burns was the very best diplomatic representative that America had in the years leading up to the great unraveling. A reader wishes he was still in government but wonders if even he could make much of a difference.

The Back Channel

A Memoir of American Diplomacy and the Case for Its Renewal

By William J. Burns

Random House. 501 pp. $32