Preemptive Strikes, Deterrence, and Denuclearization: Ascertaining Pyongyang’s View of U.S. Use of Force Against Iran’s Nuclear Program

The U.S. bombing of key sites related to Iran’s nuclear program has, not surprisingly, generated much debate over the wisdom of such strikes in light of their justification, efficacy, impact on Iran’s capabilities and intent going forward, prospects for future dialogue, and broader global nonproliferation goals. Have strikes convinced Tehran to accelerate toward a bomb faster than they would have considered prior to the strikes? Was diplomacy, particularly under the Joint Comprehensive Plan of Action, given sufficient opportunity to walk Iran away from the path of nuclearization, or was diplomacy merely a means by which Iran could mitigate pressure while covertly moving down a path that was inevitable from the beginning? With the program likely not entirely obliterated, has the bombing nevertheless laid the groundwork for making clear that the United States is prepared to take bold military action to further degrade and impede the growth of the program? For each of these questions, additional data and a commitment to depoliticized and objective assessments will be needed to go beyond what is understood today.

Pyongyang’s Perspective

The impact of these strikes on North Korea (DPRK) requires deeper discussion as well. Although Pyongyang media have justified their nuclear development over the past 30 years by pointing to the threat and “hostility” of the United States, the relatively slow and methodical nature of the program’s development would suggest a lack of urgency or perceived existential crisis by North Korea. Since the beginning of the DPRK “nuclear crisis” in the early 1990s, military options have been discussed and explored multiple times: by President Clinton in 1994, President Bush in 2002, and President Trump in 2017.In each case, the use of force was rejected out of both a concern of uncontrollable escalation even at the conventional level, as well as uncertainty as to such actions’ ultimate efficacy in discouraging Pyongyang from continuing on the nuclear path. Although it may seem natural to ask whether the recent U.S. strike on Iran may hint at opportunities with North Korea, three decades of experience suggest neither the United States nor its ally, South Korea, is willing to consider such a path.

Demise of Diplomacy?

The next natural question is what harm U.S. actions have on nonproliferation diplomacy globally, and prospects for denuclearization diplomacy with North Korea specifically. In this regard, more serious reflection and debate are required, as is a realistic assessment as to the likelihood of meaningful diplomacy with North Korea in the near term. While there has been a recent flurry of policy proposals on the need for the Trump administration to pursue diplomacy, most of these recommendations downplay DPRK agency and thus fundamentally miss the point that, since Kim Jong-un’s post-Hanoi loss of interest in pursuing diplomacy with the United States, Pyongyang has been absolutely nonresponsive over the past five or so years. Multiple approaches by the Biden administration were rejected, and it appears Kim Jong-un has been no more flexible in responding to initial overtures from President Trump. Contrary to assertions of multiple critics of U.S. policy toward North Korea, it has not been that the United States has set the bar unreasonably high by asking for complete and verifiable denuclearization of North Korea while missing the opportunity for more incremental advances that might restrain further growth while managing tension and escalation through arms control–like dialogue. It is that Kim Jong-un simply is not interested in dialogue with countries unprepared to accept North Korea as an irreversible nuclear power as Russia, for example, has proven to be of late.

For these reasons, it’s a stretch to say that President Trump’s decision on the Iran strikes closes any window for dialogue with Kim Jong-un. There is near unanimity on the assessment that Kim Jong-un, in viewing the U.S. strikes on Iran, likely feels justified and emboldened by the fact that he has nuclear weapons and Iran does not, which is why Iran gets bombed and North Korea does not. It has been, however, decades since North Korea embarked on the path to nuclear weapons, and it would be wrong to see the June 2025 strikes as the definitive straw that broke the camel’s back: When it comes to prospects for a negotiated path to denuclearization, odds for denuclearization of the Korean Peninsula are no better or worse as a result of the June strikes.

Driving the Deterrence Discussion

Beyond the denuclearization question, it is useful to consider whether President Trump’s decision to use force against Iran diminishes or enhances U.S. deterrence efforts on the Korean peninsula. Deterrence—particularly extended deterrence or the promise of the United States of a nuclear umbrella to protect South Korea—depends to a great degree on one’s view of U.S. intentions and reliability as a security provider. The erosion of South Korea’s confidence in the U.S. extended deterrence in the 2021–2023 period did not reflect diminished confidence in U.S. nuclear capabilities. Rather, it reflected Seoul’s skepticism of Washington’s intent and willingness to use its capabilities in response to potential nuclear use by North Korea. The April 2023 Washington Declaration and subsequent Nuclear Consultative Group meetings have established a more institutionalized structure to help reassure South Korea of U.S. extended deterrence but such reassurances are not a “one-and-done” event. New leadership in both Seoul and Washington will likely require a relook at the extended deterrence demand signal from the new Lee Jae-myung administration as well as the extent of the commitment that the Trump administration will be inclined to provide.

In this regard, President Trump’s willingness to use force to promote the strategic objective of preventing a nuclear Iran sends a strong signal to those in either South or North Korea who might otherwise have perceived the United States under President Trump withdrawing from the global stage and reluctant to use force where its interests and its ally’s interests are at stake. Kim Jong-un has seen B-2s fly to the Korean Peninsula numerous times in the past, deployments designed, in the words of the U.S. Department of Defense, to “demonstrate the United States’ ability to conduct long range, precision strikes quickly and at will.” Kim has seen inert dummy rounds delivered on these stealth aircraft making the long 6,500 mile, 37-and-a-half hour flight from Whiteman Air Force Base in Missouri to North Korea and back. The theoretical capability has been vividly demonstrated. Now he and the world have seen the B-2 fly 7,000 miles for 37 hours to successfully drop live munitions on underground facilities in Iran. U.S. intelligence assesses North Korea’s underground facility program as “the largest and most fortified in the world,” with these facilities designed to “protect and conceal regime leaders, weapons of mass destruction, ballistic missiles, warfighting stores, and elements of military forces and defense industries.” The June 2025 U.S. strike demonstrates that even at the conventional level, the United States can hit key leadership, weapons of mass destruction, and other military targets throughout North Korea in response to any DPRK aggression.

Harmonizing Seoul’s and Washington’s Approaches to the North Korea Issue

The advent of the Trump and Lee Jae Myung administrations is inevitably going to lead to discussions on how to keep the engagement and deterrence efforts in balance. Efforts at promoting peace on the Korean Peninsula must take place in coordination with actions to ensure and enhance deterrence. Such coordination is key given that the orientation of both leaders toward North Korea is markedly different from that of their respective predecessors. Although at times frustrating, this approach has worked in the past and will likely continue to going forward.

Deterrence requires (1) a clear demonstration of intent to punish in response to threatening actions by one’s adversary, (2) assurance to allies that the U.S. commitment will be fulfilled, and (3) reassurance to one’s adversary that good behavior will be reciprocated. But questions remain: When will extended deterrence muscles need to be flexed? How will goodwill and assurance gestures toward Pyongyang be deployed? How should combined exercises be designed, orchestrated, and signaled to maintain and demonstrate readiness? What should be done when trilateral U.S.-South Korea-Japan exercises generate push-back from Pyongyang, Beijing, and Moscow?

Over the history of North Korea’s nuclear development, the United States has had periods of engagement and attempts to assure Pyongyang of the benefits of reconciliation and denuclearization, and periods in which strong demonstrations of deterrence were deemed necessary, given North Korea’s increased capabilities and aggressive behavior. Engagement allows for probing intentions and confirming the judgment of skeptics that denuclearization is unlikely. Deterrence reminds Pyongyang of the price of its program. So far, deterrence has held, and door remains open to dialogue whether or not Kim Jong-un decides to reengage.

Before making policy recommendations, an objective assessment of past efforts is crucial. Often there is sloppiness in understanding agency and causality. It was not hardline policies of conservative leaders in Seoul that led Pyongyang to conduct six nuclear tests, hundreds of missile launches, the sinking of South Korean vessels, and the shelling of a South Korean island. Conversely, engagement pursued by progressives did not result in cataclysmic atrophy of military readiness and capitulation to the North. Appeasement has not lead to aggressive exploitation by Pyongyang, and aggressive hardline policies in Seoul have not lead to uncontrolled escalation or advancement of the nuclear program.

Intentionality of respective leaders aside, the cumulative policies of Seoul and Washington over the past three decades have resulted in a mix of (1) compellance, making clear the price Pyongyang would pay for nuclear adventurism, (2) assurance of allies in Seoul and Tokyo of the U.S. extended deterrent, and (3) reassurance to Pyongyang that while failing to halt the growth of North Korea’s nuclear program, and they have prevented dangerous or unwanted escalation of tension on the Peninsula. Deterrence has held over some seven decades of armistice.

Putting Pyongyang at Ease

To understand how the Lee administration may approach North Korea, there is value in reviewing North Korea’s demands of the Moon Jae-in administration that impacted Seoul’s and even Washington’s DPRK policy during the critical years of 2017–2019. Upon returning from a March 2018 trip to Pyongyang, then director of South Korea’s National Security Office Chung Eui-yong quoted Kim Jong-un as having made clear his “commitment to the denuclearization of the Korean Peninsula,” asserting that North Korea would “have no reason to possess nuclear weapons should military threats against the North be removed and the safety of its regime be guaranteed.”

On the one hand, this formulation was not new: I personally had seen this over the years of watching North Korean media, and also sat across the table from North Korean officials using this very same language. Claiming an inveterate U.S. hostile policy has been routinely interpreted as Pyongyang’s justifying narrative for its nuclear program and why North Korea could never surrender its weapons. The “military threat removal” language was usually defined as reducing and eliminating U.S.-ROK military exercises, reducing and eliminating strategic asset deployments such as B-52 and B-2 flights, and reducing and eliminating U.S. Forces in Korea. This likely would be the framework today for any “arms control” approach in U.S.-DPRK dialogue, with Pyongyang’s logic being that there is no way the DPRK could consider limits or controls on its nuclear weapons not otherwise agreed to by the United States. In other words, when the U.S. security commitment to South Korea is removed, then North Korea might consider talking about its nuclear program.

System or regime safety is a more abstract and thus difficult challenge. What actions must—or even can—the United States and South Korea take to make sure North Korea’s “system” is “safe” or “stable”? The 2018 demand came in the aftermath of a more aggressive unification push by Moon Jae-in’s conservative predecessor Park Geun-hye, so immediately there began a flow of reassurances from the Moon Administration, and then later in 2018 by U.S. officials, including Secretary of Defense Jim Mattis and Secretary of State Rex Tillerson, of non-hostility and non-intent to overthrow the Kim regime or pursue unification. South Korean loudspeaker broadcasts along the demilitarized zone were halted, crackdowns on launches of propaganda balloons by NGOs were carried out, and efforts to discourage defections were carried out to seek to remove as many irritants (“hostile actions,” to use North Korea’s term) as possible from the relationship. Not surprisingly, Pyongyang did not reward Seoul’s goodwill, and inter-Korean relations returned to the status quo ante level of animosity and tension beginning in 2019.

Giving Appeasement a Chance?

Sir Lawrence Freedman is often quoted as warning, “Deterrence works, until it doesn’t,” a reminder of the need for humility in assessing the efficacy or success of deterrence and actions taken in support of that goal. Its corollary is also worth considering: “Appeasement works, until it doesn’t.” There is near-term political value in having calm and quiet on the Korean Peninsula, even as centrifuges spin and missiles move down the assembly line. At a time when Pyongyang might not be in listening (or talking) mode, leaders in Seoul and Washington have other target audiences for their North Korea policy. Domestic policies and politics in both South Korea and the United States often emerge as the dominant considerations and drivers for North Korea policy, particularly when Pyongyang is in a diplomatic shutdown mode as it is now. One might bemoan either a perceived excessively hardline approach of conservatives or the ostensibly naïve engagement approach of progressives. Yet such swings are to be expected, and there may be an argument that in the longer term these shifts could be seen as complementary and necessary, not necessarily irrevocably harmful to deterrence objectives.

Which gets back to the June 22 U.S. airstrikes on Iran. It’s hard to believe that Pyongyang is significantly more committed to its nuclear program than it was on June 21—or at any time in the recent past. There have been no indications that Kim was preparing to positively respond to U.S. calls for dialogue, and that U.S. actions have undermined this in any way. Any lesson the United States may have hoped Kim Jong-un would receive was most likely not “you’re next if you don’t denuclearize.”

So deliberately or not, the message sent, and the message that Kim Jong-un likely received, was one of U.S. intent and U.S. capabilities. Contrary to conventional wisdom, Donald Trump is not an isolationist afraid of using force in the advancement of U.S. security interests. Current concerns about U.S.–South Korea relations and the state of the alliance aside, Kim should not miscalculate a lack of will on Washington’s part to come to the defense of South Korea if attacked by North Korea. Another important lesson from the June strike is that the United States has unique capabilities to project power; capabilities such as B-2 bombers and GBU-57 Massive Ordinance Penetrators can fly long distances and hit critical underground targets. That may not get Kim Jong-un to the negotiating table, but it is likely to keep him out of the war room.

Sydney Seiler is a senior adviser (non-resident) with the Korea Chair at the Center for Strategic and International Studies (CSIS) in Washington, D.C.

The views expressed in this submission are the author’s and do not imply endorsement by the Office of the Director of National Intelligence, the Intelligence Community, or any other U.S. government agency.