It was not until June 6, 1944, four years later, that the allies landed on the Normandy coast. Over 200,000 troops, in a 48-hour period, in the largest amphibious operation in history, stormed the beaches to do what the Germans thought impossible. Eight months later, Germany was defeated.

The cost was high, however. With the German Army facing little opposition in the Rhineland, Austria, or Czechoslovakia, the German invasion West into the low countries and France was easy. Western Europe fell in a matter of three months from April to June 1940. At the end of the day, once deterrence was lost, World War II led to the death of over 60 million people. Getting deterrence back was a tough proposition.

In 1949, the United States withdrew its military from the Republic of Korea. Then, in January 1950, the US Secretary of State, Dean Acheson, asserted that the Republic of Korea (ROK) was beyond the US defense perimeter. In early June, the US Congress approved an aid package for the ROK, but it was not delivered until after the North Korean invasion that began on June 25, 1950. Undermining American deterrence of North Korea with Acheson’s speech ultimately cost 2 million Korean lives and nearly 200,000 allied casualties.

Although the US was able to reestablish deterrence in Korea seven decades later, in 2014, the United States lost effective deterrence once again—this time in Europe. That was the year Washington declared that Ukraine was not of interest to the United States, leaving Ukraine to the tender mercies of the Russian Army. Russia soon took Crimea and ultimately launched a brutal invasion in 2022.

In 2021, the US withdrew ignobly from Afghanistan, further signaling the nation’s enemies that the US was not in the deterrence business. The consequences of that act are still unknown.

Later in 2021, the administration hesitated in making it clear whether Washington would or would not defend Ukraine from further Russian aggression. Though the mistake was later rectified, the damage to deterrence was done.

Further harm came to Ukraine, the US, and the North Atlantic Treaty Organization’s (NATO) European member states when it became clear Washington was fearful of a Russian escalation of the conflict should the allies get serious about pushing back against Russian aggression. Russian President Vladimir Putin repeatedly threatened the use of nuclear weapons should Ukraine and the allied coalition get serious about rolling back Russia’s aggression—the successful use of Russian deterrence.

To counter the American loss of deterrence, Congress agreed to markedly increase defense spending and investments in America’s nuclear deterrent, space capability, and missile defense. Over time, and coupled with a sense of urgency, the United States can restore deterrence if these new investments are sustained.

The nation’s legacy nuclear deterrent, which is now between 35 to 65 years old, will soon age to obsolescence. The Sentinel intercontinental ballistic missile (ICBM), Columbia-class ballistic missile submarine (SSBN), and the B21 Raider strategic bomber, along with the long-range nuclear cruise missile, once built, will markedly restore nuclear deterrence. An improved theater nuclear deterrent, with a new sea-launched nuclear cruise missile and a stand-off nuclear capability for the F-35, would also significantly improve deterrence.

These systems give the nation the capability required to deter China and Russia. However, the second part of deterrence is will. Whether the United States has the will to employ its deterrent capability is uncertain.

How the administration handles Iran will say a great deal about how adversaries see American will. The administration is committed to preventing Iran from getting a nuclear weapon. Washington said you could do this the easy way or the hard way. A negotiated deal is one way but military strikes on Iran’s nuclear infrastructure is the other.

With the Israelis and Americans on the same page and the war already begun, the die is now cast and the US does not have endless patience. But whether it is willing to use military force is uncertain. Although Henry Kissinger once said that diplomacy without the threat of force is without effect, the conventional wisdom in Washington is that no military action will be forthcoming.

The Trump administration carefully laid out a challenge to the Iranians. There were 60 days for negotiations. Now, it is widely known that on day 61 the Israelis, with US missile and air defense assistance, took out most of the above ground Iranian nuclear capability as well as the top Iranian nuclear leadership.

Perhaps Israeli deterrence credibility was restored, but whether that is true of the United States is far less certain. The Trump administration did what it said it would do. The Israelis did what they had to do. Both nations did what was necessary to restore deterrence. The Iranian nuclear capability is gone. How this will affect Chinese and Russian aggression, that requires more insight.

Peter Huessy is a Senior Fellow at the National Institute for Deterrence Studies.

Restoring Deterrence was originally published on Global Security Review.

This issue is not new. In his 1957 book Nuclear Weapons and Foreign Policy, Henry Kissinger made a controversial, yet analytically compelling, argument for the possible utility of tactical nuclear weapons in limited wars. He warned that massive retaliation was neither credible nor effective for deterring limited aggression and that a rigid dichotomy between conventional and strategic nuclear responses risked inviting coercion at the lower rungs of the escalation ladder. For Kissinger, introducing the possibility of limited nuclear use was not a call to war, but a recognition of strategic reality; the ability to escalate with restraint could deter adversaries from escalating first.

Fast forward to the 2030 scenarios modeled in Guardian Tiger I and II, and Kissinger’s insights remain disturbingly relevant. In the exercise, North Korea carried out a low-yield nuclear strike targeting South Korean naval vessels. American decision-makers, faced with the risk of horizontal escalation with China and the lack of consensus among allies, struggled to identify a proportional yet credible response. The idea of a retaliatory tactical nuclear strike was floated, but the simulated American leadership hesitated, reflecting both doctrinal ambiguity and an operational gap in American nuclear capabilities.

The risks of such hesitation are manifold. First, American restraint may be misinterpreted as indecision or weakness, particularly by allies like South Korea and Japan, who are directly exposed to North Korean and Chinese threats. Second, it creates an opening for adversaries to believe they can escalate to the nuclear level without inviting proportional retaliation. Third, it undermines the entire architecture of extended deterrence that underpins regional security.

Critics will rightly point out the perils of normalizing nuclear use. Introducing tactical nuclear weapons into a conflict zone invites moral hazards, increases the risk of miscalculation, and breaks long-standing nuclear taboos. It also challenges existing declaratory policies, such as the 2022 P5 Joint Statement affirming that “a nuclear war cannot be won and must never be fought.”

But these arguments, while valid in principle, must be weighed against the operational reality that a low-yield nuclear strike by an adversary may not be deterred by threats of massive retaliation. As the Atlantic Council report noted, North Korea’s nuclear doctrine increasingly incorporates elements of pre-delegated authority, tactical nuclear use, and efforts toward a more survivable second-strike posture. If the United States signals that it will not respond proportionally to a limited nuclear attack, North Korea may calculate that it can use nuclear weapons to coerce the South or constrain American action without triggering regime-ending consequences.

Moreover, the credibility problem is not confined to North Korea. China, observing Washington’s reluctance to respond in kind, may also be emboldened to engage in horizontal escalation, confident that the United States’s nuclear threshold is politically—and perhaps operationally—immobile. This perception could unravel the strategic coherence of integrated deterrence.

To address these challenges, US Forces Korea (USFK) and Indo-Pacific Command should adopt a more robust approach across multiple dimensions. First, the United States should consider forward-deploying platforms capable of delivering low-yield nuclear weapons. This could include the reintroduction of dual-capable aircraft or sea-based assets positioned in or near the Korean Peninsula. Such deployments must be both survivable and possess the ability to clearly signal an adversary of will, while being fully integrated into bilateral operational planning with the Republic of Korea (ROK).

Second, escalation options must be clarified through updates to American declaratory policy. This does not mean issuing public ultimatums or fixed thresholds but rather ensuring that adversaries understand the United States is willing to conduct proportional nuclear responses if deterrence fails. Strategic ambiguity must not become strategic paralysis.

Third, while the US and South Korea launched the Nuclear Consultative Group (NCG) in 2023 to enhance extended deterrence coordination, further institutionalization is needed. A structure modeled more closely on the North Atlantic Treaty Organization’s (NATO) Nuclear Planning Group would help deepen transparency, signal unity of purpose, and reduce the risk of fragmented responses during crises.

Fourth, both US and ROK forces must be equipped and trained to operate in the aftermath of a limited nuclear strike. This includes rehearsals and exercises focused on base survivability, radiological detection and decontamination, logistics continuity, and the resilience of command-and-control (C2) systems.

Fifth, strategic communication must be strengthened. Clear and consistent messaging to both adversaries and allies is critical. Deterrence depends not only on military capabilities, but also on the perceived credibility of those capabilities and the intentions behind them.

Ultimately, the goal of these measures is not to normalize the use of nuclear weapons, but to reinforce the threshold against their use by making deterrence more credible and responsive.

If that threshold is ever crossed and the United States fails to respond proportionately, the credibility of its extended deterrence architecture could unravel. The Guardian Tiger exercises highlight this grim possibility and should serve as a clarion call to action for policy and defense leaders alike.

As Kissinger warned in 1957, the danger of total war arises not so much from a deliberate decision to embark on it as from a series of actions which, though rational in themselves, cumulatively lead to disaster. The United States must ensure that its rational desire to avoid nuclear escalation does not lead to an irrational loss of deterrence. Tactical nuclear flexibility, responsibly exercised and credibly signaled, may be the painful but necessary insurance policy to uphold peace in East Asia.

Dr. Ju Hyung Kim, President of the Security Management Institute, a defense think tank affiliated with the South Korean National Assembly, is currently adapting his doctoral dissertation, “Japan’s Security Contribution to South Korea, 1950 to 2023,” into a book.

The Case for US Low-Yield Nuclear Options in Korea was originally published on Global Security Review.

The Implications of a Nuclear Armed South Korea with Lieutenant General In-Bum Chun (ROK, Ret) was originally published on Global Security Review.

North Korea, a relic of the Cold War, has evolved into a cult state centered around the Kim family. Despite its oppressive regime, the state’s endurance into the 21st century is perplexing. The regime maintains its grip on power through a combination of brainwashing, terror and strict social control. Public executions and pervasive surveillance cultivate an environment of fear, ensuring blind obedience from the population. However, beneath this veneer of control, North Korean society is sustained by bribery and corruption, which permeate every level of life.

Read the full article here.

Balloons and sleepwalking into conflicts was originally published on Global Security Review.