On the Brink: How NATO's 'Eastern Sentry' Is Testing the Thin Line between Deterrence and War with Russia

Following the increase in Russian missile attacks on Ukraine and the identification of several unidentified flying objects in the airspace of Baltic countries and other European nations, a series of deterrent measures have been implemented by NATO members. These developments have once again turned Eastern Europe into the axis of a security dispute between the West and Moscow, and on a broader level, have brought the concept of deterrence against asymmetric threats back to the center of political discourse in Europe.

Recently, the Baltic countries—Lithuania, Latvia, and Estonia—along with Poland, have raised their air alert levels and intensified their operational coordination with NATO's central command in Brussels. This decision was made after repeated reports of unidentified objects flying over NATO's eastern borders and Russian missile attacks on western regions of Ukraine. According to various reports, as part of the operation codenamed "Eastern Sentry," NATO fighter jets from European member states are conducting rotational flights over the Baltic Sea to provide 24-hour air coverage on the alliance's eastern flank. This action, beyond its military aspect, carries a clear political message for Moscow: that NATO does not intend to remain passive in the face of Russian aerial threats.

Furthermore, some analysts see these movements as a sign of a profound shift in NATO's defense philosophy. In this framework, the traditional reactive approach is giving way to a policy of preemptive deterrence, or displaying strength for peace; meaning that NATO seeks to neutralize threats before they materialize. While this shift has led to increased readiness and cohesion within the defense structure, it also harbors the risk of strategic miscalculation. In reality, any rapid reaction could be interpreted by Russia as an aggressive move, paving the way for unintended conflicts and leading Europe into a major challenge.

However, among the Baltic countries, Lithuania has been a pioneer in implementing the rapid reaction policy more than others. The suspension of commercial flights at the country's international airport and the deployment of air defense units on the border with Belarus are signs of the full implementation of NATO's new doctrine. The Lithuanian government has announced that any potential threat from the east, from spy drones to unidentified flights, will be intercepted if they enter the country's defense radius—although this statement is more of a political message than having practical operational capability, it is examinable within the framework of NATO's new approach.

Additionally, this action, beyond its military dimensions, carries a political message to European allies that small countries, within the framework of NATO's collective security, want to play an active role in their own defense and no longer wait for the decisions of major powers. This policy could also serve as a model for NATO's border countries facing hybrid threats—threats where the line between military, cyber, and psychological operations has blurred.

On the other side, Poland, as the new pivot of European security, has gained a decisive role. Following the violation of its airspace by unidentified drones in September 2025, Warsaw activated Article 4 of the North Atlantic Treaty for the first time since the Cold War. In response, NATO launched Operation Eastern Sentry with a focus on Poland, and the Polish government also signed contracts worth $3.8 billion to modernize its F-16 fighter jets and develop anti-drone systems. These developments have turned Poland into NATO's strategic hub in Eastern Europe. While such a position increases deterrence power, it has also intensified Moscow's political and military pressure on Warsaw.

However, it must be noted that the recent crisis is not solely military in nature; its media and psychological dimension has also gained particular importance. Extensive coverage of these events in international media has plunged European public opinion into a state of anxiety and distrust. According to France's *Le Monde*, following the violation of Polish airspace, an unprecedented volume of misinformation and psychological operations was disseminated on social media to undermine public trust in NATO and reinforce a sense of insecurity. In such an atmosphere, security discourse has replaced diplomatic discourse, and rapid military reaction has become the standard for political legitimacy. This phenomenon is very important from the perspective of international politics because it shows that 21st-century wars are not only fought on the military battlefield but also continue in other domains, and the winner is the one who controls the primary narrative and the dominant discourse.

Alongside this, the increase in security alerts in Eastern Europe could signal the beginning of a new phase in the European Union's defense policy. At the structural level, NATO is expected to establish a more permanent presence on its eastern flank; from constructing new air bases in Poland and Lithuania to deploying interception systems in the Baltic countries, and bold resolutions by the European Parliament targeting hostile objects in European skies—all point to a shift in Europe's approach.

Furthermore, NATO members, especially in Eastern Europe, will be compelled to increase their defense budgets and restructure their forces. This trend could fuel a new arms race between the West and Russia, while also leading to increased domestic pressures due to reduced social services and higher taxes. But the main danger lies in the gradual erosion of the diplomatic process; because a state of permanent readiness undermines mutual trust and increases the likelihood of strategic miscalculations. In an environment where any military movement can be perceived as a threat, the smallest incident could turn a regional crisis into a global one.

Finally, what is unfolding in Eastern Europe today is not merely an escalation of tension, but the formation of a kind of unstable and fragile deterrence; a situation where security is maintained through a display of power, but this very display of power can become a new factor for instability. Europe now more than ever needs to strike a precise balance between power and diplomacy. Without such a balance, a continent that has managed to maintain its stability with difficulty for decades may once again find itself on the brink of a comprehensive arms race—a competition that blurs the line between deterrence and actual conflict in the most dangerous way possible, with the people of Europe and even the world being its victims.

Translated by Ashraf Hemmati from the original Persian article written by Amin Mahdavi

cepa.org
www.eurointegration.com.ua
https://www.reuters.com/business/aerospace-defense/poland-signs-38-billion-deal-upgrade-f-16-fighter-jets-2025-08-13

https://www.lemonde.fr/en/international/article/2025/10/08/poland-hit-by-unprecedented-disinformation-attack-following-russian-drone-incursion_6746208_4