The United States has long relied on a nuclear triad consisting of land-based intercontinental ballistic missiles (ICBMs), strategic bombers, and nuclear-powered ballistic missile submarines (SSBNs). This triad has been supported by the past four US presidential administrations as the most effective means to maintain deterrence at a reasonable cost. However, emerging risks suggest that US government decisions in the coming years could inadvertently weaken the viability of this triad.
The three components of the triad work in concert, creating a system that is greater than the sum of its parts. SSBNs are widely recognized as the most survivable leg during conflicts, remaining virtually undetectable while at sea. ICBMs are seen as the most responsive leg of the triad due to their round-the-clock alert status, ready to launch at a moment’s notice. On the other hand, strategic bombers are viewed as the most flexible and visible leg, capable of being deployed in plain sight to reassure allies and deter adversaries.
Together, the three legs of the triad provide numerous advantages, including enhanced survivability and assured retaliation. This combination also promotes strategic stability through redundancy and flexibility in various scenarios. The triad allows the United States to tailor its deterrence strategies to different adversaries while mitigating risks that could result from technological advancements or shifts in geopolitical dynamics.
However, changes in the composition of the triad that disrupt the balance of US nuclear capabilities can provoke vulnerabilities that undermine deterrence. The effectiveness of the triad hinges not only on its three components but also on the balance among them regarding numbers and capabilities. Any shift that significantly alters this balance could weaken one or multiple legs of the triad, leading to decreased deterrence.
In light of these complexities, the Trump administration is not expected to abandon the triad entirely, and its endorsement of the existing nuclear modernization program appears firm. Nevertheless, there are emerging stressors that could compromise the triad’s effectiveness and credibility. A key risk could arise if the United States reduces its commitment to one of the triad’s components or disproportionately relies on one leg, thereby undermining the balance among them.
Three particular stressors highlight the potential risks posed by imbalances among the triad’s components in upcoming years. First, SSBNs have been historically viewed as nearly invulnerable, which has led to suggestions of increased reliance on this leg. Proposals to expand the SSBN fleet could lead to a disproportionate increase in weapons within this component relative to the other two.
Second, the escalating costs associated with the Sentinel ICBM program have sparked discussions within the US Air Force about the acquisition strategy. With costs projected to soar 81 percent higher in 2024 than originally estimated, pressure may mount to scale back the program. While Congress remains fully supportive of the Sentinel program—a plan to replace the Minuteman III ICBM one-for-one—the possibility of a smaller number of deployed Sentinels looms if costs continue to rise significantly. Such a pivot could result in a reduced quantity of ICBMs in the land leg compared to the other two, ultimately affecting the balance.
A third consideration lies in the ongoing development of the B-21 Raider program, which is progressing steadily. Many commentators advocate for a higher number of B-21 bombers, which could lead to an increased emphasis on the bomber leg relative to the other two components.
Any decision to adjust the triad’s composition may seem justifiable in light of evolving security environments and available funding. However, such changes should be approached with caution, as they carry the risk of introducing new vulnerabilities. Policymakers must recognize that overlooking these emerging threats could lead adversaries to perceive new opportunities for preemptive attacks in manners that US strategists might have previously overlooked.
In particular, technological advancements pose heightened risks to the sea leg of the triad. Innovations in unmanned surface and subsurface drones could make it progressively easier to locate and track US submarines. Additionally, advancements in quantum sensing technologies might render submarines more susceptible to detection using sophisticated acoustics, magnetometry, and gravimetry.Capturing these threats, the Defense Intelligence Agency cautioned earlier this year that quantum technologies are rapidly approaching battlefield viability.
The limited number of SSBNs—particularly when not on heightened alert—further complicates this issue, given that they carry a substantial portion of the US’s deployed warheads. If adversaries can target these submarines more effectively due to emerging technologies, new vulnerabilities that destabilize US nuclear posture could arise.
The risks are similarly pronounced concerning US strategic bombers. The B-2 Spirit and B-52 Stratofortress, stationed at bases in the continental United States, reside in exposed areas or unhardened hangars. Similar concerns have been raised regarding the B-21 Raider, which may also be housed in unhardened shelters, echoing vulnerabilities observed in previous operational contexts.
The recent Operation Spiderweb, conducted by Ukraine in June 2025, offers a stark warning. This operation witnessed Ukrainian special forces successfully utilizing unmanned aerial vehicles to attack more than 40 Russian strategic bombers while in Russian territory. Such operations present a potential model for adversaries like China or Russia, who could leverage similar tactics against US bombers based within the United States.
US ICBM silos and corresponding launch infrastructure face heightened obstacles as well. In the event of a crisis, drones capable of carrying explosives or shaped charges could be deployed from various locations to compromise control centers or missile silos, stifling the United States’s capacity to launch ICBMs swiftly.
Given these mounting risks, it is imperative for the United States to maintain a balanced distribution of capabilities across the three legs of the nuclear triad. Overemphasis on one leg or decreased focus on another could yield vulnerabilities that policymakers will regret, particularly since it takes years to develop and implement new or modified capabilities due to ongoing challenges within the defense industrial base and nuclear enterprise.
As US leaders contemplate potential adjustments to the size, posture, or composition of nuclear forces, they must carefully weigh these considerations. They should recognize that the repercussions of their choices today will reverberate for decades to come.
Paul Amato, the former director for nuclear deterrence policy in the Office of Secretary of Defense for Policy, articulates these concerns based on his extensive experience, including twenty-eight years of active and reserve service as a Marine infantry officer. The opinions expressed in this analysis are solely those of the author.
In addition, it’s worth noting that the Atlantic Council’s Scowcroft Center for Strategy and Security is actively examining nuclear and strategic forces, funded by a range of donors, including corporations in the defense sector and the US government. These contributions underscore the importance of maintaining robust and effective nuclear deterrent capabilities to secure national interests.
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