With his customary keen insight, the Financial Times commentator Edward Luce recently observed that GOP nominee Donald Trump’s Achilles heel is a lack of character. Because of this, Trump’s opponents argue, he cannot be trusted with oversight of the U.S. nuclear arsenal.  In a recent Wall Street Journal op-ed piece, former U.S. Senator Sam Nunn (D. Ga.) asserted that of the two presidential candidates, only Hillary Clinton has “experience, judgment and skills” to have a finger on the figurative “nuclear button.”

At the third presidential debate, Clinton herself argued that Trump is unfit to be commander-in-chief. Specifically alluding to Trump’s proposal that Japan and South Korea develop their own nuclear arsenals, she charged that he is “very cavalier, even casual about the use of nuclear weapons.” Clinton may have scored a debating point here, but her foreign policy record demonstrates that  - even if for different reasons - her views on nuclear weapons are at least as reckless as Trump’s. To understand why, we need to go back to the Cold War, when the United States used its nuclear arsenal to protect Western Europe from a potential Soviet attack.

After World War II, nuclear strategists distinguished between two different types of deterrence: direct deterrence and extended deterrence. Direct deterrence is the use of U.S. nuclear weapons to dissuade an adversary from launching a premeditated strike on U.S. territory.  Effective direct deterrence is easy, not hard. It requires only that the United States retains what is called a secure second strike retaliatory force - an arsenal capable of inflicting unacceptable damage even if an adversary attacks the United States first. Direct deterrence works because other states understand the consequences of attacking American soil: they would be subjected to devastating U.S. retaliation. That is a risk that adversaries will not run. After all, states and the regimes that govern them want to survive, not to kill themselves. In this sense, the much lampooned Cold War strategic doctrine of Mutual Assured Destruction (MAD) remains robust.

America’s vulnerability to nuclear war has always come from another quarter: bringing overseas U.S. allies in Europe and East Asia under the shelter of the so-called nuclear umbrella. This strategy is called extended deterrence. Extended deterrence was foundation of U.S. and NATO strategy during the Cold W because the alliance chose to rely on American nuclear weapons for security rather than building conventional forces capable of defeating a non-nuclear Soviet attack.

Transatlantic security relations during the Cold War drove home a point that was seldom debated openly back then, and seems to be forgotten today: although direct deterrence is easy, extended deterrence is hard. Very hard. Why? Because, as Patrick Morgan, an expert on nuclear strategy at the University of California, Irvine, explains: “One of the perpetual problems of deterrence on behalf of third parties is that the costs a state is willing to bear are usually much less than if its own territory is at stake, and it is very difficult to pretend otherwise.” For extended deterrence to work it must be credible. This means that the United States must convince potential adversaries, and reassure allies, that it if push comes to shove, it will do what it says will do: use nuclear weapons to protect its allies. The problem, however, is that nuclear deterrence is inherently incredible because rational states do not commit suicide to protect others. America’s adversaries know that, and so do its allies.

Transatlantic security relations during the Cold War were always fraught because of the built-in tensions created by the NATO’s extended deterrence strategy. Indeed, the alliance’s cohesion was frequently stretched to the breaking point because of the conflicting strategic interests of the United States and Western Europe. Of course, policymakers on both sides of the Atlantic strived to avoid war with the Soviet Union. But as the “wizards of Armageddon” - the priesthood of nuclear strategists in think tanks and the defense ministries - played out possible conflict scenarios, U.S. and West European strategists each developed their respective versions of the “perfect war.” For the Americans, it was a conventional and/or tactical nuclear war fought in Europe (principally in Germany). For the Europeans, it was a war where the superpowers’ ICBMs flew high above an untouched continent on their way to the Soviet and American homelands. 

During the Cold War, to reassure the West Europeans, and deter the Soviets, the United States was forced to adopt a very dangerous strategic posture on the Continent. Washington tried a number of expedients to convince the West Europeans that the United States would commit suicide on their behalf: trying to attain a first strike advantage (counter-force or damage limitation capability in nuke-speak), using tactical nuclear weapons, and then intermediate range nuclear weapons (INFs) to link the U.S. strategic nuclear arsenal to the continent’s defense. In essence, the United States - to use Thomas C. Schelling’s image - “threw the steering wheel out of the car” in a deliberate attempt to tie its hands so that a Soviet conventional attack on Western Europe would have escalated virtually automatically to a strategic nuclear exchange between the superpowers.  In other words, U.S. strategy was designed to lock in Washington to doing reflexively what it would not do rationally. 

Of course, the Cold War in Europe never became hot. This does not mean, however, that extended deterrence “worked.” Rather, America’s security commitment to Western Europe never was tested, because there is no evidence suggesting that during the entire period from World War II’s end to the Soviet Union’s collapse, the Kremlin ever planned to initiate a war of conquest against Western Europe. Of course, it is a good thing that the U.S. security guarantee to Western Europe was not tested by the Soviets, because the United States would have paid a horrendous price for honoring it. Indeed, for precisely this reason, extended deterrence was a contentious issue that repeatedly stretched NATO's cohesion to the breaking point. 

Throughout the Cold War, the West Europeans doubted that the United States actually would use nuclear weapons on their behalf. In 1961, French President Charles de Gaulle told President John F. Kennedy that Europe could never believe that the United States really would risk the destruction of New York in order to save Paris. Equally, because they understood the risks to their own country, some perceptive American policymakers were uncertain whether the United States should - or would - risk nuclear war to protect Western Europe. In 1959, for example, Secretary of State Christian A. Herter stated: “I can’t conceive of the President of the United States involving us in an all-out nuclear war unless the facts showed clearly that we are in danger of devastation ourselves, or that actual moves have been made toward devastating ourselves.” Twenty years later, in Brussels, speaking (supposedly off-the-record) at the annual meeting of the Institute for International Strategic Studies, former Secretary of State Henry  A. Kissinger - echoing Herter’s concerns - asked: “Don’t you Europeans keep asking us to multiply assurances we cannot possibly mean, and that if we do mean, we should not want to execute, because it would destroy our civilization?”  

Such candor from senior officials about U.S. nuclear strategy was - and remains - rare. It comes as no surprise, therefore, that the American public remained blissfully unaware of the implications of U.S. Cold War strategy. In 1984, at the height of the crisis caused by the NATO decision to deploy U.S. INFs in Europe, a Public Agenda Foundation survey showed that over 80 percent of Americans incorrectly believed that the United States’ policy was to use nuclear weapons only to retaliate for a nuclear attack on the American homeland. Doubtless, this is what most Americans believe - wrongly - about U.S. nuclear strategy today.

Notwithstanding its illogic, during the Cold War, U.S. nuclear strategy did not lead to catastrophe. The absence of superpower conflict in Cold War Europe is explained by two factors. First, the historical record (including the opened portions of Soviet diplomatic archives) shows that Moscow never contemplated a deliberate - “bolt out of the blue” - attack on Western Europe. Second, after 1948, the demarcation line between the respective U.S. and Soviet zones of control in Europe was sharply delineated, and respected on both sides. Today, however, extended deterrence is facing new tests in both the Baltic States, and - even more perilously - in East Asia.

East Asia today is much different from Cold War Europe from 1950 to 1989. First, while the Soviet Union was barely half a superpower (except with respect to nuclear weapons), China’s economy already has surpassed that of the United States’. Unlike a tottering Soviet Union, China is a great power on the rise. Second, East Asia is a region where there are dangerous geopolitical flashpoints: the Korean Peninsula, the South China Sea, the Diaoyu/Senkaku Islands, and Taiwan, which China considers an integral part of Chinese territory. During the Cold War, the dilemmas of extended deterrence in Europe were essentially abstract. They allowed the wizards of Armageddon to engage in navel gazing exercises about the metaphysics of nuclear strategy. In East Asia, however, the perils associated with extended deterrence are acutely concrete. If the United States sticks to its present alliance relationships with Japan, South Korea, and Taiwan (which is a de facto U.S. security protectorate), the risk of being entrapped by its alliance commitments in a nuclear conflict with North Korea, or - far more concerning - China is all too real.

The rising Sino-Japanese antagonism is worrisome because of the security treaty between the United States and Japan. Because of its obligations, the United States almost inevitably would find itself involved in a nuclear conflict arising out a military clash between China and Japan. Here, the rival claims asserted by Beijing and Tokyo to the Diaoyu/Senkaku Islands well could provide the spark. In October 2010, this once obscure dispute became a front page story when a Chinese trawler illegally fishing in Japanese controlled waters rammed a Japanese coast guard vessel - thus setting off a major diplomatic row between the two big Asian powers. 

If the fate of these islands only concerned China and Japan, it would not be the potential cause of a grave geopolitical crisis. But it’s not just about them; it’s also about the United States because of Washington’s security treaty with Japan.  As Secretary of State, Hillary Clinton, on several occasions, explicitly stated that the United States is obligated by treaty to come to Japan’s assistance if war with China breaks out because of the two powers’ competing claims to sovereignty over the islands. This is not just worst-case scenario thinking. Since the fall of 2010 hardly a week has gone by without some kind of Sino-Japanese crisis concerning these islands. 

During the Vietnam War, President Lyndon Johnson referred to North Vietnam as a “piss ant” country. By this definition, the Daioyu/Senkaku Islands are a bunch of piss ant rock piles in the East China Sea. They may be important symbolically (or, if speculation about undersea mineral resources is correct, economically) to Beijing and Tokyo. But they have no intrinsic value to the United States, and it is the height of folly to commit the United States to risk a possible nuclear war to defend them. The fact that Hillary Clinton has done so raises troubling questions about her foreign policy judgment.

The fate of Taiwan also poses the risk of a Sino-American War. Although not formally tied by treaty to Taiwan’s security, the United States in practice is committed to defend Taiwan from China. In 1996, there was a crisis when China started lobbing missiles just off Taiwanese controlled waters to influence the Taiwanese elections. The United States responded to Beijing’s actions by sending two aircraft carrier battle groups through the Straits of Taiwan, which resulted in a Chinese climb-down. But few recall is what happened afterward. A senior Chinese official told the American diplomat Chas. W. Freeman that in a future Sino-American crisis, the United States would never repeat its 1996 show of force. As the Chinese official noted, China was growing ever stronger militarily, and in the future, the risks to the United States of challenging it would rise steeply. The United States would not run those risks the Chinese official said, because future Washington policymakers would “care more about Los Angeles than they do about Taiwan.”

As the late football coach George Allen was fond of saying at the start of every season, the future is now. Twenty years have passed since the 1996 Taiwan Straits crisis, and in both nuclear and conventional capabilities, China is rapidly closing the gap military gap with the United States. Indeed, as Deputy Defense Secretary Robert O. Work recently observed, “China and Russia are developing battle networks that are as good as our own. They can see as far as ours can see; they can throw guided munitions as far as we can.” In East Asia today, all of the Cold War nightmares about extended deterrence have come back with a vengeance.

Donald Trump has taken lots of flak for suggesting that South Korea and Japan acquire their own nuclear weapons. For sure, Trump lacks the intellectual framework to articulate why such a policy actually is eminently sensible - and Hillary Clinton’s foreign policy thinking is too ossified to understand the logic underlying such a policy. Others, however, have articulate the reasons why the United States should get out of the extended deterrence business, and devolve the primary responsibility for defending themselves to the United States’ security dependents. And the more insightful recipients of those guarantees understand full well that, faced with the real possibility of nuclear war, the United States would not honor them. Certainly, Charles de Gaulle, one of the twentieth century’s towering statesmen, and an astute student of geopolitics, realized this. Understanding that the United States could not be trusted to commit suicide for Western Europe, he grasped the implications of this insight: France needed to acquire its own nuclear arsenal. Today, in South Korea and Japan, a similar discussion among policymakers is taking place. And every now and then it rises to the surface in newspaper stories and journal articles that detail the growing sentiment in official circles that both of these states need to go nuclear because neither can continue to rely on American promises to risk nuclear conflict on their behalf.

The idea of any nuclear proliferation is, of course, anathema to the hidebound U.S. foreign policy establishment. For them, the response to endangered allies in East Asia and the Baltic States is that the United States should step up its efforts to “reassure” its security dependents.  This is exactly the wrong policy for two reasons. First, it ultimately will not work. States that have the wherewithal to adopt strategies of direct deterrence, like Japan and South Korea, increasingly are aware that the U.S. strategy of extended deterrence is not credible. Second, giving unconditional security guarantees to other states raises potential strategic moral hazard issues. 

Several years ago at a conference in Sweden, a senior Estonian diplomat was asked whether his government was concerned that its discriminatory policies toward its minority ethnic Russian population might prompt Moscow to intervene militarily. His answer was that Estonia neither needed to worry about Russia, nor change its policies because the United States would protect it come what may. When asked during the October 2010 Sino-Japanese crisis in the East China Sea what Tokyo would do a decade or two hence if fiscal and domestic political pressures caused the United States to retrench in East Asia., a senior foreign ministry official said that Japanese leaders did not think about such hypotheticals, because the United States would always protect Japan.

This is not the kind of thinking American policy should encourage. Rather than a policy of reassurance, Washington should adopt a policy of de-assurance and make it clear to our security dependents that they need to do a lot more to defend themselves, even if that means acquiring nuclear weapons. Rather than perpetuating European, Japanese, South Korean dependence on the United States, the United States should be nudging them down the path of a more independent strategic posture. Although it may sound counterintuitive to non-experts, some prominent scholars have argued that the world would actually be more stable if Washington re-considered its blanket opposition to nuclear proliferation. 

Decades ago, the late Kenneth Waltz - perhaps the most preeminent U.S. thinker about international politics of the post World War II era - compellingly argued that a world of more nuclear-armed states could be safer and more stable than a world of fewer nuclear weapons states. The reason, he said, is that direct deterrence is credible but extended deterrence is not.  Waltz did not advocate promiscuous, indiscriminate, uncontrolled proliferation. But states like Japan and South Korea today meet his criteria. They are modern, wealthy, politically stable states that can build, and maintain, survivable nuclear deterrent forces. And they are not Pakistan; they can safeguard their nuclear forces and ensure they don’t fall into the hands of terrorist groups.

However, the American foreign policy establishment - of which Hillary Clinton is a card-carrying member - is aghast a the idea of retracting U.S. extended deterrence guarantees, and allowing Japan and South Korea to provide for their own security. They prattle on with cliches about the indispensability of America’s leadership, and the continuing importance of U.S. alliances. (Recently Mrs. Clinton called the United States the world’s indispensable nation. This was an act of foreign policy plagiarism because she was regurgitating verbatim the words of Madeleine Albright, her husband’s Secretary of State.) The American foreign policy establishment has its stock arguments for the grand strategic status quo of basing U.S. policy on extended deterrence: the United States must defend its allies, uphold regional security in East Asia and Europe, maintain its credibility, and continually demonstrate its resolve. But except for the rare exceptions of a Herter or Kissinger, members of the foreign policy establishment never level with the American people and acknowledge the risky nuclear strategy that underpins these catch-phrases.

Extended nuclear deterrence is an old think approach to American grand strategy that fails to acknowledge that today’s world is one of profound geopolitical change. The halcyon days of unipolarity and American primacy are over. The American foreign policy establishment clings to shopworn policies devised in a very different age, and refuses to acknowledge the risks of staying the course rather than thinking innovatively about American grand strategy. Most of all, the foreign policy establishment fails to understand that rather being a force for peace and stability in places like the Baltics and East Asia, U.S. alliances are really transmission belts for war that will bring overseas conflicts to American soil. If war breaks out in these regions, the United States will be sucked into potentially nuclear conflicts arising over issues that do not affect America’s fundamental security. Rational policymakers should not want their states to commit suicide for the sake of allies. No ally’s fate is important enough for the United States to risk a nuclear war. In a nuclear world, American lives matter. America First is not an epithet, it is a strategic imperative.

Christopher Layne is University Distinguished Professor of International Affairs, and Robert M. Gates Chair in National Security, at Texas A&M University.

Image: A 15-kiloton test fired from a 280-millimeter cannon on May 25, 1953 at the Nevada Proving Grounds. Wikimedia Commons/Public domain