THE GREY ZONE: How Russia Can Pressure Europe Without Starting a War

As the war in Ukraine rages on, Europe faces a difficult question: how should it deal with Russia? Recent reports of direct communication with Putin have divided opinion, with some seeing diplomacy as necessary and others questioning the value of engaging a leader they believe is not serious about peace.

This week, we examine the grey zone between peace and war, where sabotage, cyberattacks and threats to critical infrastructure challenge Europe’s response. These actions may not justify military retaliation, but they are too serious to ignore. How can Europe respond decisively without risking a wider conflict?

EUROPE VULNERABLE FROM WEST TO EAST

Europe’s vulnerability is not a lack of military power, as discussed in previous articles. It is the growing uncertainty surrounding its reliance on the United States. For decades, European security has depended on NATO’s collective defence, underpinned by American military strength and Washington’s commitment to defend its allies. However, mixed signals from the Trump administration regarding NATO commitments, burden-sharing and the broader transatlantic relationship have raised questions about how reliably the United States would respond to a serious crisis in Europe. The issue is not that American support has formally disappeared, but that uncertainty about Washington’s willingness to act can weaken deterrence before a crisis even begins. Russia may see an opportunity to exploit these doubts, testing European resolve while probing the limits of American commitment.

Cyberattacks, sabotage, disinformation and pressure on critical infrastructure can undermine public trust, fuel social discord and expose divisions between European governments. Russia understands how to exploit these vulnerabilities while operating below the threshold of open conflict. By keeping individual incidents ambiguous, deniable or limited in scale, it can make a decisive response politically difficult. Such actions may not trigger Article 5 of the North Atlantic Treaty, but their cumulative impact can still threaten European security. The challenge for Europe is to recognise that remaining below the threshold of collective military response does not make these activities any less serious.

THE ATTRIBUTION PROBLEM

Another reason why responding to grey-zone activities is so difficult is the challenge of attribution. Those carrying out acts of sabotage may not be directly linked to the state suspected of orchestrating them. Russia can exploit intermediaries, criminal networks and individuals recruited through social media platforms or Telegram to carry out small, seemingly isolated tasks in exchange for money. These individuals may have little knowledge of who is ultimately directing the operation or what strategic purpose it serves. This creates layers of separation between the act itself and those potentially responsible for organising it, making investigations more complex and public attribution more difficult. Even when an incident appears suspicious, establishing a credible link to the Russian state requires evidence that can withstand scrutiny.

Europe must therefore navigate a delicate balance in its response. Inaction risks encouraging further operations by signalling that the costs of sabotage remain low. Yet an excessive or poorly substantiated response could escalate tensions, undermine Europe's credibility or provoke further confrontation. The answer lies in combining thorough investigations and intelligence-sharing with proportionate measures that reflect the available evidence. Where direct attribution remains uncertain, governments can still strengthen infrastructure protection, disrupt recruitment networks and impose consequences on those directly responsible when the law permits. The objective is not to respond impulsively to every suspected provocation, but to ensure that uncertainty does not become a shield behind which hostile activities can continue without consequence.

CAN EUROPE IMPOSE MEANINGFUL COSTS WITHOUT TRIGGERING A CONFRONTATION?

Europe must move beyond expressions of concern and adopt a more decisive approach to sabotage, attacks on critical infrastructure and other grey-zone activities that threaten its security. Every incident must be investigated thoroughly, intelligence shared across borders, and the evidence examined to establish not only who carried out an attack, but who ordered, financed or facilitated it. Where evidence points to Russian state involvement, European governments must build the strongest possible evidentiary case, distinguishing verified facts from intelligence assessments and reasonable suspicion. Attribution may not always achieve absolute certainty, but public accusations and punitive measures must rest on evidence proportionate to the seriousness of the response. Anything less risks undermining Europe's credibility and giving hostile actors an opportunity to exploit divisions among its allies.

Once responsibility has been established, Europe must send a clear and credible message that attacks on its infrastructure and security will carry consequences. This could include coordinated diplomatic action, targeted sanctions, disruption of the networks facilitating sabotage, stronger protection of vulnerable infrastructure and, where legally justified, additional proportionate measures agreed with European partners. The objective should not be retaliation for its own sake, but deterrence: making it clear that covert operations cannot be conducted repeatedly without imposing meaningful costs on those responsible. 

Unity is essential. If individual European countries respond inconsistently, potential adversaries may conclude that ambiguity and political division offer effective protection from consequences. Europe's response must therefore combine rigorous investigation, resilient infrastructure and collective resolve. The message should be unmistakable: Europe will establish the facts, identify those responsible and respond with determination within the bounds of law.

THE INTELLIGENCE DILEMMA

How should governments respond when intelligence suggests hostile intent, but public evidence is insufficient to prove responsibility? This is the central dilemma of grey-zone warfare. Inaction risks encouraging further attacks, while accusations without solid evidence can undermine credibility and escalate tensions.

Europe must balance continued support for Ukraine with maintaining its strategic relationship with the United States. Yet uncertainty cannot become an excuse for paralysis. Through coordinated sanctions, stronger counterintelligence and improved infrastructure protection, European governments must demonstrate unity and resolve. The message to Moscow should be clear: Europe will not tolerate hostile activities, and ambiguity will not be mistaken for weakness.

2027 SCENARIOS

Looking ahead to 2027, Russia’s grey-zone activities in Europe could intensify. Drone incursions and suspected deliberate overflights have already raised concerns about airspace security, while incidents involving undersea cables have highlighted the vulnerability of critical infrastructure. Further sabotage targeting electricity networks, water supplies and other essential services cannot be ruled out. Such operations could create public anxiety, disrupt daily life and test the ability of European governments to respond collectively.

At the more serious end of the spectrum, Europe must also consider the possibility of covert operations involving unmarked personnel, similar to Russia’s use of so-called “little green men” during the seizure of Crimea in 2014. Such a scenario would present an acute challenge if the individuals’ identities, command structures and state connections remained unclear. These are possibilities, not predictions, but they underline the need for stronger preparedness. Europe must improve its ability to detect, attribute and deter hostile activities before ambiguity becomes a strategic advantage for the adversary.

CONCLUSION

Europe cannot afford to wait for a crisis to decide where its red lines lie. If grey-zone activities intensify in 2027, the real test will not simply be whether European countries can identify the threat, but whether they can act together despite uncertainty, political divisions and the risk of escalation. Russia may exploit the space between suspicion and proof, and between provocation and open conflict. 

Europe must close that gap through stronger intelligence cooperation, resilient infrastructure and a coordinated response that imposes meaningful consequences when responsibility is established. Deterrence does not require Europe to escalate every incident, but it does require consistency, credibility and resolve. 

The greatest danger is not that Europe lacks the power to respond, but that uncertainty prevents it from acting until the cost of inaction becomes far greater.