The exchange of social media messages between US President Trump and Russia’s former President Medvedev, culminating in the latter’s nuclear threat against the US, unexpectedly led President Trump to announce that he had ordered two nuclear submarines to “appropriate locations” in response. While it is unclear what this entails, the surprisingly strong US signal is useful for deterring Russia’s nuclear coercion.
At the beginning of August, messaging on social media between US President Trump and Russia’s former President Medvedev escalated into an episode of public nuclear signalling. After Medvedev issued what was widely perceived as a nuclear threat against the US, Trump responded by announcing that he had ordered two nuclear submarines to “appropriate locations”.
The content of Trump’s message suggests that he did not craft it alone, but rather with the help of other members of his national security team. The message was carefully composed, in contrast to the reckless style of Trump’s past nuclear threats against North Korea and his typical social media posts. Notably, Dmitry Medvedev’s title was correctly identified as Deputy Chairman of the Security Council, which Trump did not appear to know in an interview he gave shortly after the message was published. Trump also confirmed the involvement of others when he later explained that “we did not think” that Russia’s threat was appropriate. Therefore, President Trump’s decision should not be understood as solely his personal reaction, but rather as a calculated US response to Russia’s nuclear sabre-rattling.
While the details are unclear, Trump likely referred to ballistic missile submarines (SSBNs), which are known to operate in varying states of readiness during deterrent patrols. Some SSBNs are on-alert, patrolling designated areas and ready to launch; some are on modified alert and prepared to replace the on-alert boat if needed; while others are not within range or in position of their priority targets. While it is unclear what changed operationally, it is likely that the US order resulted in some improvement in the combat readiness of the US sea-based deterrent.
Although it is not a major change, adjusting the SSBN posture is still a meaningful act. The accuracy and diverse warhead-yield options of the Trident D5 submarine-launched ballistic missile (SLBM) make it suitable for a variety of pre-planned nuclear options, some of which also involve cross-targeting with other nuclear delivery vehicles and utilize their different flight trajectories. Some options benefit from close proximity to the target, as this reduces early warning time, an advantage that SLBMs have over land-based Minuteman III missiles.
The US deterrent signal is also innovative because SSBNs are typically considered to have less signalling utility than strategic bombers, whose patrols are visible to the adversary. Using bombers in this case, however, would have been an inappropriately strong measure that could have led to a Russian response and a public outcry. By publicly specifying the change in SSBN posture in sufficient detail, the US was able to tailor a message that was both effective and low risk.
Russia, for its part, had no reason to react to US signalling. The US made it clear that its goal was only to deter Russia and, with silo-based missiles on constant alert and some SSBNs already on alert, the changes in posture were too minor to require adjustments to Russia’s own nuclear posture. Moreover, a major feature of Russia’s strategic culture, as a counterpart to its preference for offence, is the fear of being drawn into a reactive mode and taking rash decisions that compromise its long-term goals. Russia exercises restraint if it perceives a tactical advantage in doing so, as it did in this case. Its fundamental interest lies in detaching the US from the war in Ukraine, not in igniting a nuclear crisis with the US for no good reason. Instead, Russia has an interest in portraying the US as an irresponsible actor in its deterrence signalling, although in reality the opposite is true.
The US nuclear signal is significant because it is the first time President Trump has shown readiness to deter Russia’s nuclear coercion with nuclear deterrence, especially after previously undermining US deterrence by expressing concern over “World War III” during his meeting with President Zelenskyy in early 2025. While the Biden administration’s readiness to deter Russia from using nuclear weapons against Ukraine was clear, the Trump administration’s policy has been less so.
Although the US response was not directly related to Ukraine, and US policy remains uncertain should Russia turn the war in Ukraine into a nuclear crisis again, the US has at least established a baseline of readiness to react to Russia’s nuclear threats in a surprisingly strong manner. Russia will have to consider the possibility that the US will respond in a similar manner in the future. As deterrence is preventive by nature, such signals are best sent during periods of relative calm, when they can be used to shape expectations about future behaviour, rather than only during the crises they seek to prevent.
Moreover, while it is unlikely that Trump is aware of the matter, the US decision is in fact in line with the US concept of deterrence operations, according to which such operations are dynamic and tailored to the adversary. In this case, the US acted in line with both parameters, tailoring deterrence to Russia in a way that seeks to instil doubt about Russia’s ability to control deterrence interactions and to increase its perception of the risks involved in making nuclear threats.
If the US nuclear signal had been directed at a status quo-seeking nuclear power without a valid reason, it would have been irresponsible. In this case, however, the overarching context was Russia’s revisionist nuclear coercion in the war in Ukraine. With Russia constantly applying pressure on the norm against nuclear use, the stability of deterrence is an illusion. For stability to become reality, it must be continuously maintained by status quo-defending powers, which, in these circumstances, can only be achieved by pushing back. Ignoring Russia’s nuclear threats will not stop them; worse, it risks creating the impression that such threats could succeed at a critical moment.
Photo: US Navy / Andrew McPeek
