In his new book, the 91-year-old statesman strikes a note of humility

When Henry Kissinger talks about world order, to some it might seem as if he is living in a previous century. The 17th, perhaps. Beginning with his Harvard doctoral dissertation 60 years ago, he has extolled the concept of international order that was established in 1648 by the Peace of Westphalia, which ended the Thirty Years’ War. Instead of being shaped by wars of religion and the death spasms of the Holy Roman Empire, Europe’s international system was thenceforth based on independent nation-states, each sovereign over religion and other issues in its own territory. States would not interfere in the internal affairs of other states, and order would, ideally, be maintained by clever statesmen who focused on national interests and curated a balance of power.

Kissinger’s appreciation for order, he later recalled, came after his family fled Hitler’s Germany in 1938 and arrived in New York, where he realized he did not have to cross the street to avoid non-Jewish boys who might beat him up. Kissinger became an exemplar of the realist, as opposed to idealist, school of diplomacy, someone who believed that a foreign policy that is overly guided by moral impulses and crusading ideals was likely to be dangerous. “The most fundamental problem of politics,” he wrote in his dissertation, “is not the control of wickedness but the limitation of righteousness.”

Kissinger’s fellow students in Harvard’s government department scoffed at his choice of topic. The atom bomb, they contended, had fundamentally changed global affairs. One snidely suggested he should transfer to the history department.

Likewise, we are tempted to raise an eyebrow at the news that Kissinger, now 91, has produced another paean to the Westphalian system, his 17th book in 60 years, this one titled simply World Order. Respect for sovereignty? How quaint! Hasn’t he heard that in the 21st century, threats respect no borders, the world is flat, and we have a humanitarian duty to protect people in places where regimes are repressive? That is why we rejected realist thinking for a “Freedom Agenda” that included invading Iraq to make the Middle East safe for democracy, toppling Muammar Gaddafi in Libya under a humanitarian banner and seeking (well, at least until ISIS came along) to do the same to President Bashar Assad in Syria.

Hmmm…upon reflection, maybe throwing out the Westphalian system, forsaking the principle of respect for sovereignty and letting idealism overwhelm ­realism wasn’t such a good idea after all. And if that’s the case, then Kissinger’s World Order doesn’t seem dated at all. The U.S. might do well to heed his prescription that it alloy its idealism with a new dose of realism. “Westphalian principles are, at this writing, the sole generally recognized basis of what exists of a world order,” he notes.

Kissinger’s book takes us on a dazzling and instructive global tour of the quest for order, from Cardinal Richelieu to Metternich and Bismarck, the Indian minister Kautilya of the 4th century B.C. and the Ottoman Sultan Suleiman, and a succession of American Presidents beginning with Teddy Roosevelt and Woodrow Wilson, all culminating in a world order based on sovereign nation-states at the end of World War II. “By the mid-20th century,” Kissinger writes, “this international ­system was in place on every continent.”

When he was the co-pilot of American statecraft as Richard Nixon’s National Security Adviser and Secretary of State in the early 1970s, Kissinger was able to manipulate the levers of this system with a mastery that would have mesmerized Metternich. Eschewing our differences in ideologies and values, he forged a détente with the Soviet Union and an opening to China, then played off both to create a triangular balance of power that preserved the U.S.’s influence after its retreat from Vietnam.

But sustaining such a values-neutral pursuit of strategic interests is difficult in a democracy that celebrates its moral exceptionalism. “The United States has alternated between defending the Westphalian system and castigating its premises of balance of power and noninterference in domestic affairs as immoral and outmoded,” he writes. Because he and Nixon failed to weave in the idealism that is ingrained in the American DNA, popular support for their realist edifice was precarious, as if built of bricks without straw. Kissinger was attacked by moral idealists of the left and, more notably, by the nascent neoconservatives and ardent anticommunists on the right. Reaction against his realism contributed to the elections of both Jimmy Carter and then Ronald Reagan.

Although Kissinger routinely notes the importance of America’s idealism, he almost invariably follows with the word but. “America would not be true to itself if it abandoned this essential idealism,” he writes. “But to be effective, these aspirational aspects of policy must be paired with an unsentimental analysis of underlying factors.” This “yes, but” balance, with the emphasis always tilting to the but sentence, pervades Kissinger’s analysis and peppers every chapter of his book.

The need for a renewed realism, Kissinger convincingly argues, is especially true in the Middle East, where jihadists have shattered the nation-state system in their quests for global revolution based on extremist religious values. This dangerous upheaval was facilitated in part by the U.S.’s morally motivated but strategically dubious decisions to support regime change and Western-style democracy in Iraq, Libya, Egypt, Afghanistan and Syria.

On Afghanistan, Kissinger supported the initial attack on al-Qaeda and its Taliban protectors, but he looks back skeptically on the broader mission that had evolved by 2003. “The central premise of the American and allied effort became ‘rebuilding Afghanistan’ by means of a democratic, pluralistic, transparent Afghan government whose writ ran across the entire country,” he writes. But this “radical reinvention of Afghan history” was not achievable. “No institutions in the history of Afghanistan or of any part of it provided a precedent for such a broad-based effort.”

Likewise on Iraq, Kissinger initially supported the mission to topple Saddam Hussein, but he says, “I had doubts, expressed in public and governmental forums, about expanding it to nation building and giving it such universal scope.” He blames George W. Bush and his Administration for pursuing idealistic crusades that ignored earthly realities. As Bush put it in a 2003 address, “Iraqi democracy will succeed—and that success will send forth the news, from Damascus to Tehran, that freedom can be the future of every nation.” This ideal was, Kissinger notes, unmoored from realities. “To seek to achieve [American values] by military occupation in a part of the world where they had no historical roots,” he writes, “imbued the American endeavor in Iraq with a Sisyphean quality.”

Despite heart surgery this year, Kissinger at 91 is a lion in a prolonged winter. Four decades after he last served in government, he is a fixture on the New York–Washington Acela, and he makes regular trips to Russia and China, where he is still accorded meetings with top leaders. His analyses remain prescient. Just as the showdown over chemical weapons in Syria was building last year, Kissinger was at a New York City dinner where various military and intelligence experts were discussing what might happen. Kissinger predicted that Russia would suddenly step in and offer a way to resolve the chemical-weapons issue, since it and the U.S. shared a strategic interest in not having such weapons fall into terrorist hands. Two weeks later, that is precisely what happened. He also argued that it was a mistake to make the ouster of President Assad’s regime a policy objective without knowing what would replace it, because that was likely to lead to a chaotic civil war dominated by the most radical of the jihadist forces.

For his undergraduate thesis in 1950, Kissinger tackled “The Meaning of History.” At 383 pages, it attempted to tie together the philosophies of Immanuel Kant, Oswald Spengler and Arnold Toynbee, while roping in ideas from Descartes, Dostoyevsky, Hegel, Hume, Socrates and Spinoza. It was topped off with a section called “A Clue From Poetry,” featuring Dante, Homer, Milton and Virgil. At one point he declared, “Descartes’ cogito ergo sum was not really necessary.”

Kissinger ends his latest book on a different note, one of humility—a trait that for most of his career he was better at humorously feigning than at actually possessing. “Long ago, in youth, I was brash enough to think myself able to pronounce on ‘The Meaning of History,’” he writes. “I now know that history’s meaning is a matter to be discovered, not declared.”

The key to Kissinger’s foreign policy realism, and the theme at the heart of his magisterial new book, is that such humility is important not just for people but also for nations, even the U.S. Making progress toward a world order based on “individual dignity and participatory governance” is a lofty ideal, he notes. “But progress toward it will need to be sustained through a series of intermediate stages.”

Isaacson is the CEO of the Aspen Institute and a former managing editor of Time. He is the author of biographies of Henry Kissinger, Benjamin Franklin, Albert Einstein and Steve Jobs, and of The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution, to be published in October

New research shows a good night's rest isn't a luxury--it's critical for your brain and for your health

When our heads hit the pillow every night, we tend to think we’re surrendering. Not just to exhaustion, though there is that. We’re also surrendering our mind, taking leave of our focus on sensory cues, like noise and smell and blinking lights. It’s as if we’re powering ourselves down like we do the electronics at our bedside–going idle for a while, only to spring back into action when the alarm blasts hours later.

That’s what we think is happening. But as scientists are now revealing, that couldn’t be further from the truth.

In fact, when the lights go out, our brains start working–but in an altogether different way than when we’re awake. At night, a legion of neurons springs into action, and like any well-trained platoon, the cells work in perfect synchrony, pulsing with electrical signals that wash over the brain with a soothing, hypnotic flow. Meanwhile, data processors sort through the reams of information that flooded the brain all day at a pace too overwhelming to handle in real time. The brain also runs checks on itself to ensure that the exquisite balance of hormones, enzymes and proteins isn’t too far off-kilter. And all the while, cleaners follow in close pursuit to sweep out the toxic detritus that the brain doesn’t need and which can cause all kinds of problems if it builds up.

This, scientists are just now learning, is the brain on sleep. It’s nature’s panacea, more powerful than any drug in its ability to restore and rejuvenate the human brain and body. Getting the recommended seven to eight hours each night can improve concentration, sharpen planning and memory skills and maintain the fat-burning systems that regulate our weight. If every one of us slept as much as we’re supposed to, we’d all be lighter, less prone to developing Type 2 diabetes and most likely better equipped to battle depression and anxiety. We might even lower our risk of Alzheimer’s disease, osteoporosis and cancer.

The trouble is, sleep works only if we get enough of it. While plenty of pills can knock us out, none so far can replicate all of sleep’s benefits, despite decades’ worth of attempts in high-tech pharmaceutical labs.

Which is why, after long treating rest as a good-if-you-can-get-it obligation, scientists are making the case that it matters much more than we think. They’re not alone in sounding the alarm. With up to 70 million of us not getting a good night’s sleep on a regular basis, the Centers for Disease Control and Prevention considers insufficient sleep a public-health epidemic. In fact, experts argue, sleep is emerging as so potent a factor in better health that we need a societal shift–and policies to support it–to make sleep a nonnegotiable priority.

THE CONSEQUENCES OF SKIMPING

Despite how great we feel after a night’s rest–and putting aside what we now know about sleep’s importance–we stubbornly refuse to swallow our medicine, pushing off bedtime and thinking that feeling a little drowsy during the day is an annoying but harmless consequence. It’s not. Nearly 40% of adults have nodded off unintentionally during the day in the past month, and 5% have done so while driving. Insomnia or interrupted sleep nearly doubles the chances that workers will call in sick. And half of Americans say their uneven sleep makes it harder to concentrate on tasks.

Those poor sleep habits are trickling down to the next generation: 45% of teens don’t sleep the recommended nine hours on school nights, leading 25% of them to report falling asleep in class at least once a week, according to a National Sleep Foundation survey. It’s a serious enough problem that the American Academy of Pediatrics recently endorsed the idea of starting middle and high schools later to allow for more adolescent shut-eye.

Health experts have been concerned about our sleep-deprived ways for some time, but the new insights about the role sleep plays in our overall health have brought an urgency to the message. Sleep, the experts are recognizing, is the only time the brain has to catch its breath. If it doesn’t, it may drown in its own biological debris–everything from toxic free radicals produced by hard-working fuel cells to spent molecules that have outlived their usefulness.

“We all want to push the system, to get the most out of our lives, and sleep gets in the way,” says Dr. Sigrid Veasey, a leading sleep researcher and a professor of medicine at Perelman School of Medicine at the University of Pennsylvania. “But we need to know how far we can really push that system and get away with it.”

Veasey is learning that brain cells that don’t get their needed break every night are like overworked employees on consecutive double shifts–eventually, they collapse. Working with mice, she found that neurons that fire constantly to keep the brain alert spew out toxic free radicals as a by-product of making energy. During sleep, they produce antioxidants that mop up these potential poisons. But even after short periods of sleep loss, “the cells are working hard but cannot make enough antioxidants, so they progressively build up free radicals and some of the neurons die off.” Once those brain cells are gone, they’re gone for good.

After several weeks of restricted sleep, says Veasey, the mice she studied–whose brains are considered a good proxy for human brains in lab research–“are more likely to be sleepy when they are supposed to be active and have more difficulty consolidating [the benefits of] sleep during their sleep period.”

It’s the same thing that happens in aging brains, she says, as nerve cells get less efficient at clearing away their garbage. “The real question is: What are we doing to our brains if we don’t get enough sleep? If we chronically sleep-deprive ourselves, are we really aging our brains?” she asks. Ultimately, the research suggests, it’s possible that a sleep-deprived brain belonging to a teen or a 20-year-old will start to look like that of a much older person.

“Chronic sleep restriction is a stress on the body,” says Dr. Peter Liu, professor of medicine at Harbor-UCLA Medical Center and L.A. Biomedical Research Institute. And the cause of that sleep deprivation doesn’t always originate in family strife, financial concerns or job-related problems. The way we live now–checking our phones every minute, hyperscheduling our days or our kids’ days, not taking time to relax without a screen in front of our faces–contributes to a regular flow of stress hormones like cortisol, and all that artificial light and screen time is disrupting our internal clocks. Simply put, our bodies don’t know when to go to sleep naturally anymore.

This is why researchers hope their new discoveries will change once and for all the way we think about–and prioritize–those 40 winks.

GARBAGEMEN FOR YOUR BRAIN

“I was nervous when I went to my first sleep conference,” says Dr. Maiken Nedergaard, the chatty and inquisitive co-director of the Center for Translational Neuromedicine at the University of Rochester. “I was not trained in sleep, and I came to it from the outside.” In fact, as a busy mother and career woman, she saw sleep the way most of us probably do: as a bother. “Every single night, I wanted to accomplish more and enjoy time with my family, and I was annoyed to have to go to bed.”

Because she’s a neuroscientist, however, Nedergaard was inclined to ask a seemingly basic question: Why do our brains need sleep at all? There are two competing evolutionary theories. One is that sleeping organisms are immobile and therefore less likely to be easy targets, so perhaps sleep provided some protection from prey. The time slumbering, however, took away from time spent finding food and reproducing. Another points out that sleeping organisms are oblivious to creeping predators, making them ripe for attack. Since both theories seem to put us at a disadvantage, Nedergaard thought there had to be some other reason the brain needs those hours offline.

All organs in the body use energy, and in the process, they spew out waste. Most take care of their garbage with an efficient local system, recruiting immune cells like macrophages to gobble up the garbage and break it down or linking up to the network of vessels that make up the lymph system, the body’s drainage pipes.

The brain is a tremendous consumer of energy, but it’s not blanketed in lymph vessels. So how does it get rid of its trash? “If the brain is not functioning optimally, you’re dead evolutionarily, so there must be an advantage to exporting the garbage to a less critical organ like the liver to take care of it,” says Nedergaard.

Indeed, that’s what her research shows. She found that an army of previously ignored cells in the brain, called glial cells, turn into a massive pump when the body sleeps. During the day, glial cells are the unsung personal assistants of the brain. They cannot conduct electrical impulses like other neurons, but they support them as they send signals zipping along nerve networks to register a smell here and an emotion there. For decades, they were dismissed by neuroscientists because they weren’t the actual drivers of neural connections.

But Nedergaard found in clinical trials on mice that glial cells change as soon as organisms fall asleep. The difference between the waking and sleeping brain is dramatic. When the brain is awake, it resembles a busy airport, swelling with the cumulative activity of individual messages traveling from one neuron to another. The activity inflates the size of brain cells until they take up 86% of the brain’s volume.

When daylight wanes and we eventually fall asleep, however, those glial cells kick into action, slowing the brain’s electrical activity to about a third of its peak frequency. During those first stages of sleep, called non-REM (rapid eye movement), the firing becomes more synchronized rather than haphazard. The repetitive cycle lulls the nerves into a state of quiet, so in the next stage, known as REM, the firing becomes almost nonexistent. The brain continues to toggle back and forth between non-REM and REM sleep throughout the night, once every hour and a half.

At the same time, the sleeping brain’s cells shrink, making more room for the brain and spinal cord’s fluid to slosh back and forth between them. “It’s like a dishwasher that keeps flushing through to wash the dirt away,” says Nedergaard. This cleansing also occurs in the brain when we are awake, but it’s reduced by about 15%, since the glial cells have less fluid space to work with when the neurons expand.

This means that when we don’t get enough sleep, the glial cells aren’t as efficient at clearing the brain’s garbage. That may push certain degenerative brain disorders that are typical of later life to appear much earlier.

Both Nedergaard’s and Veasey’s work also hint at why older brains are more prone to developing Alzheimer’s, which is caused by a buildup of amyloid protein that isn’t cleared quickly enough.

“There is much less flow to clear away things in the aging brain,” says Nedergaard. “The garbage system picks up every three weeks instead of every week.” And like any growing pile of trash, the molecular garbage starts to affect nearby healthy cells, interfering with their ability to form and recall memories or plan even the simplest tasks.

The consequences of deprived sleep, says Dr. Mary Carskadon, professor of psychiatry and human behavior at Brown University, are “scary, really scary.”

RIGHTSIZING YOUR SLEEP

All this isn’t actually so alarming, since there’s a simple fix that can stop this nerve die-off and slow the brain’s accelerated ride toward aging. What’s needed, says Carskadon, is a rebranding of sleep that strips away any hint of its being on the sidelines of our health.

As it is, sleep is so undervalued that getting by on fewer hours has become a badge of honor. Plus, we live in a culture that caters to the late-nighter, from 24-hour grocery stores to online shopping sites that never close. It’s no surprise, then, that more than half of American adults don’t get the recommended seven to nine hours of shut-eye every night.

Whether or not we can catch up on sleep–on the weekend, say–is a hotly debated topic among sleep researchers; the latest evidence suggests that while it isn’t ideal, it might help. When Liu, the UCLA sleep researcher and professor of medicine, brought chronically sleep-restricted people into the lab for a weekend of sleep during which they logged about 10 hours per night, they showed improvements in the ability of insulin to process blood sugar. That suggests that catch-up sleep may undo some but not all of the damage that sleep deprivation causes, which is encouraging given how many adults don’t get the hours they need each night. Still, Liu isn’t ready to endorse the habit of sleeping less and making up for it later. “It’s like telling people you only need to eat healthy during the weekends, but during the week you can eat whatever you like,” he says. “It’s not the right health message.”

Sleeping pills, while helpful for some, are not necessarily a silver bullet either. “A sleeping pill will target one area of the brain, but there’s never going to be a perfect sleeping pill, because you couldn’t really replicate the different chemicals moving in and out of different parts of the brain to go through the different stages of sleep,” says Dr. Nancy Collop, director of the Emory University Sleep Center. Still, for the 4% of Americans who rely on prescription sleep aids, the slumber they get with the help of a pill is better than not sleeping at all or getting interrupted sleep. At this point, it’s not clear whether the brain completes the same crucial housekeeping duties during medicated sleep as it does during natural sleep, and the long-term effects on the brain of relying on sleeping pills aren’t known either.

Making things trickier is the fact that we are unaware of the toll sleep deprivation takes on us. Studies consistently show that people who sleep less than eight hours a night don’t perform as well on concentration and memory tests but report feeling no deficits in their thinking skills. That just perpetuates the tendency to dismiss sleep and its critical role in everything from our mental faculties to our metabolic health.

The ideal is to reset the body’s natural sleep-wake cycle, a matter of training our bodies to sleep similar amounts every night and wake up at roughly the same time each day. An even better way to rediscover our natural cycle is to get as much exposure to natural light as possible during the day, while limiting how much indoor lighting, including from computer and television screens, we see at night. And of course, the best way to accomplish that is by making those seven to nine hours of sleep a must–not a luxury.

“I am now looking at and thinking of sleep as an ‘environmental exposure,'” says Brown University’s Carskadon–which means we should look at sleep similarly to how we view air-pollution exposure, secondhand smoke or toxins in our drinking water. If she and other researchers have their way, checking up on sleep would be a routine part of any physical exam, and doctors would ask about our sleep habits in the same way they query us about diet, stress, exercise, our sex life, our eyesight–you name it. And if we aren’t sleeping enough, they might prescribe a change, just as they would for any other bad health habit.

Some physicians are already taking the initiative, but no prescription works unless we actually take it. If our work schedule cuts into our sleep time, we need to make the sleep we get count by avoiding naps and exercising when we can during the day; feeling tired will get us to fall asleep sooner. If we need help dozing off, gentle exercises or yoga-type stretching can also help. Creating a sleep ritual can make sleep something we look forward to rather than something we feel obligated to do, so we’re more likely to get our allotted time instead of skipping it. A favorite book, a warm bath or other ways to get drowsy might prompt us to actually look forward to unwinding at the end of the day.

Given what scientists are learning about how much the body–and especially the brain–needs a solid and consistent amount of sleep, in-the-know doctors aren’t waiting for more studies to prove what we as a species know intuitively: that cheating ourselves of sleep is depriving us from taking advantage of one of nature’s most powerful drugs.

“We now know that there is a lasting price to pay for sleep loss,” says Veasey. “We used to think that if you don’t sleep enough, you can sleep more and you’ll be fine tomorrow. We now know if you push the system enough, that’s simply not true.”

–WITH REPORTING BY MANDY OAKLANDER AND ALEXANDRA SIFFERLIN/NEW YORK CITY