THE DANISH STRAITS CONFLICT
AND THE COMING WAR

The Danish Straits are critical maritime passages linking the Baltic Sea to the North Sea, holding immense strategic importance for both naval operations and commercial shipping. Control over these straits is vital for monitoring traffic, deterring incursions, and ensuring the free flow of maritime commerce. NATO and Denmark have deployed advanced surveillance technologies and defense measures to secure this vital corridor, aiming to enhance intelligence capabilities, prevent threats, and maintain the passage's strategic integrity.

Beyond military and security concerns, the Danish Straits are essential for global energy logistics. For over two decades, they have served as a key route for Russian oil exports to Europe, with approximately 3.2 million barrels per day of crude oil and petroleum products transiting the straits in 2016. Baltic ports like Primorsk and Ust-Luga near Saint Petersburg have become central to Russia's energy trade, further emphasizing the importance of this narrow passage.

Since the war in Ukraine and the imposition of Western sanctions, the strategic importance of the Danish Straits has increased significantly. The straits have become the main route for Russia’s "shadow fleet"—a network of illicit tankers bypassing sanctions to sustain Russian energy exports. Between January and August 2024, the number of these vessels transiting the straits surged by 277% compared to the same period in 2022. From January 2023 to mid-2024, the shadow fleet transported oil worth approximately €103 billion.

In a recent period (October 1 to November 8, 2023), over 200 vessels passed through, averaging nearly three per day. These figures underscore the Danish Straits’ critical role in sustaining Russian oil exports despite mounting international sanctions. As Western efforts to curtail Russia’s energy revenues intensify, the straits remain a key battleground in the broader contest between economic coercion and strategic evasion.

The Danish Straits Blockade of Russia’s Shadow Tanker Fleet

With the United States stepping back from its involvement in the Russia - Ukraine conflict, the European Union finds itself with no choice but to bear the brunt of not only supporting Ukraine’s war effort but also containing Russia. More so, Europe will need to implement, if necessary, measures that will cut off Russia’s access to how it finances its war machine.

One such measure would be blocking Russia’s shadow fleet from passing through the Danish Straits, all in the name of ecological safety or, more pointedly, concerns regarding the protection of undersea infrastructure, as evidenced by the recent Baltic Connector incident. Such an action, however, would inevitably ratchet up the stakes.

If the EU decides to enforce a blockade of Russian oil tankers in the Danish Straits, it would be a high-stakes move in the economic war against Russia. The primary objective would to cripple Russia’s “shadow fleet,” which operates outside Western financial and insurance systems to bypass sanctions. This action would mark a critical escalation in Europe’s strategy to cut Russian oil revenues and force the Kremlin to de-escalate the war in Ukraine. Enforcing a blockade could increase financial pressure on the Kremlin, accelerate its economic decline, and weaken its war effort in Ukraine. However, this escalation directly threatens Russia’s economic survival, meaning Moscow will be compelled to respond—whether through diplomatic maneuvering, economic retaliation, hybrid warfare, or even outright military force.

But blocking the shadow fleet poses serious strategic risks, as Russia will not simply accept economic strangulation. Instead, it will deploy countermeasures, use hybrid warfare tactics, and possibly escalate militarily. This confrontation follows the logic of economic warfare and naval power projection, leading to multiple possible scenarios.

NATO Naval Capabilities in the Baltic

NATO's naval presence in the Baltic is flexible and mission-dependent, with specific fleet numbers kept confidential for security reasons. The alliance’s assets include submarines, surface combatants, and auxiliary ships, each playing a crucial role in regional deterrence and operational sustainability. NATO maintains a fleet of destroyers, frigates, and multi-role ships equipped for air defense, anti-submarine warfare, and precision strikes. Germany deploys five stealthy Type 212A diesel-electric submarines, while Poland operates an aging Kilo-class submarine. Sweden, after joining NATO recently, has worked with the alliance and fields advanced Gotland-class submarines, some of the best non-nuclear submarines. Additionally, NATO relies on auxiliary vessels like supply ships and tankers to ensure extended operations in the Baltic.

Despite NATO’s enhanced force posture in the Baltic Sea, significant capability and capacity gaps remain in the alliance’s ability to deter and respond to Russian hybrid and conventional threats.

NATO’s ability to deter and counter Russian hybrid and conventional threats in the Baltic region will depend on its capacity to enhance force posture, improve logistical mobility, and expand mine-warfare and undersea surveillance capabilities.

Russia’s Naval Capabilities in the Baltic

Russia’s naval presence in the Baltic is limited. Its fleet includes 43 surface ships—six primary combatants (five guided missile destroyers and one frigate), 35 smaller patrol and littoral combat ships, 13 amphibious landing craft, and one submarine.

This force is not sufficient to challenge NATO's dominance in the Baltic Sea or disrupt supply lines through the Danish Straits. Instead, Russia employs asymmetric strategies, such as small-scale amphibious operations to secure strategic islands and targeting NATO resupply efforts to the Baltic States and Finland using anti-ship missile systems. Additionally, Russia may strike military and civilian infrastructure along the Baltic littoral and continue to rely on covert hybrid warfare, including sabotage, cyberattacks, and special operations within the maritime domain.

Despite the underfunding of Russia's Baltic naval forces, its undersea capabilities, particularly in disrupting critical infrastructure, are notable. Russia’s submarines can sever communication and energy links between the Baltic States and Europe. While its submarine fleet, especially its nuclear deterrent, is based in the Northern Fleet in Murmansk, rather than the Baltic Fleet in Kaliningrad, Russia continues to expand its covert operations in the Baltic, focusing on undersea infrastructure. Evidence shows that Russia is taking greater operational risks in the Baltic and the North Sea, signaling its intent to disrupt NATO infrastructure rather than seek direct military superiority.

In addition to undersea operations, Russia has strengthened its anti-access/area-denial (A2/AD) capabilities in Kaliningrad, incorporating cruise missiles, surface-to-air missiles, and nuclear-capable assets. While some of Kaliningrad’s ground forces have been redeployed due to the war in Ukraine, its air, naval, and missile assets—such as Su-24, Su-27, and Su-30 aircraft capable of launching anti-ship missiles—remain operational, making Kaliningrad a key component of Russia’s regional deterrence strategy.

Western sanctions on Russia's defense sector may affect its access to advanced electronic components, potentially diminishing the quality of its long-range precision strike capabilities. However, this is unlikely to alter Russian military doctrine, as Moscow will likely continue to seek alternative trade routes and illicit procurement channels. The West can expect Russia to rely on artillery, missiles, and advanced air defense systems, many of which surpass NATO equivalents. Moscow’s maritime doctrine prioritizes hybrid warfare, particularly in the Baltic, where it seeks to achieve its goals without crossing into direct conflict.

Despite the challenges posed by the Ukraine war and sanctions, Russia retains the ability to disrupt NATO through asymmetric tactics that exploit gaps in NATO's force structure and readiness.

Russia's Northern Fleet

Russia’s Northern Fleet, based in Murmansk, is its most formidable naval force, specializing in Arctic and North Atlantic operations. However, its ability to engage directly in the Danish Straits—key for access between the North Sea and Baltic—is hindered by geography, NATO defenses, and strategic limitations. Although the Northern Fleet possesses the firepower to challenge NATO, its power projection is limited by NATO’s dominance in the area. Any attempt to send ships through the Danish Straits would likely be intercepted long before reaching the region.

Instead, Russia would likely rely on asymmetric tactics—long-range missile strikes, submarine operations, or hybrid warfare—to disrupt NATO activities in the region. Russia may also attempt to interfere with NATO's sea lanes in the North Atlantic, targeting reinforcements and logistics bound for Europe.

Strategic Options for Europe

The overarching goal of the European blockade would be to stop Russian oil tankers while minimizing escalation risks. To achieve this, Europe has several strategic options, each with distinct advantages and potential drawbacks.

One strategy could also tighten insurance restrictions, denying coverage to vessels in the shadow fleet. Additionally, maritime nations could cooperate on tracking and seizure operations under international law, such as piracy laws. While this approach provides a legal foundation and avoids direct military conflict, shadow fleet operators may circumvent these measures by using false documents, disabling tracking systems, or finding alternative smuggling routes.

An additional approach would involve naval enforcement and interdiction. NATO navies, led by Denmark, Germany, and the United Kingdom, could block unauthorized Russian tankers from transiting the straits. Boarding and inspection operations could be conducted on suspicious vessels to verify compliance with international environmental regulations. This strategy would be effective in halting shadow fleet operations, but it carries significant risks of escalation. Russia may retaliate by deploying naval forces, launching hybrid attacks, or threatening military action to challenge NATO’s control of the straits.

An alternative strategy involves hybrid and cyber warfare against the shadow fleet. Cyberattacks could target Russian oil shipping logistics, disrupting port operations, tracking systems, and financial transactions. Electronic warfare could disable navigation systems, making shadow fleet operations riskier and harder to coordinate. Covert sabotage of Russian-controlled tankers could further hinder their efficiency. This approach limits confrontation while crippling Russia’s oil export capacity. However, cyber and hybrid tactics are difficult to trace, and such actions could provoke Russian retaliatory measures, like cyberattacks on European energy infrastructure or covert operations against Western maritime assets.

Another strategy involves applying economic pressure on countries like China, India, and other major buyers of Russian oil. The EU and its allies could threaten secondary sanctions on nations enabling Russia’s shadow fleet operations. Diplomatic and trade incentives could persuade these buyers to reduce their reliance on Russian energy. Europe could also support Western-aligned shipping and financial alternatives to make Russian oil less attractive in global markets. This approach avoids military conflict and could weaken Russia’s export economy over time. However, it depends on the willingness of major energy consumers, such as China and India, to cooperate. Given their strategic interests, these countries may resist Western pressure, prioritizing diversified energy supplies over compliance with sanctions.

Potential Scenarios of the NATO-Russia Conflict

Losing access to the Danish Straits would be a strategic blow to Russia, and it is unlikely that the Kremlin would accept such a loss without retaliation. Given the critical role these waters play in Russian energy exports and trade, Russia’s response would likely involve a combination of economic pressure, hybrid warfare, and, in extreme cases, military escalation.

Scenario 1: Hybrid Escalation and Sabotage Operations

The first stage of a confrontation could take the form of a limited hybrid conflict, where NATO intensifies sanctions enforcement by deploying naval patrols and electronic surveillance to monitor and obstruct Russian shadow fleet movements through the Danish Straits. This would be accompanied by a reinforced NATO presence under Operation Baltic Sentry, with warships from multiple member states and enhanced intelligence from Sweden, whose Gotland-based surveillance systems would offer NATO early warning and reconnaissance data.¹

Russia, unwilling to engage in direct hostilities but seeking to undermine NATO’s enforcement mechanisms, would likely resort to asymmetric tactics. Sabotage operations against NATO’s undersea infrastructure would emerge as a primary means of escalation, targeting critical energy pipelines and communication cables. Russian covert units, operating from commercial vessels or disguised under neutral flags, would attempt to sever these vital connections. NATO’s Task Force X, a fleet of unmanned naval drones (unscrewed surface vessels — USVs) dedicated to surveillance and undersea security, would likely assume a more active role in detecting and neutralizing these threats.

Electronic warfare would play a pivotal role, with Russian forces employing jamming and cyber-interference measures from Kaliningrad to disrupt NATO’s command-and-control networks in the region. In response, NATO would expand its mine warfare and anti-sabotage capabilities, intensifying defensive measures along the Baltic littoral. This scenario would remain below the threshold of conventional war, but the sustained pattern of Russian hybrid attacks could catalyze a more forceful NATO response, raising the possibility of direct military confrontation.

Scenario 2: Naval Standoff and the Strategic Significance of Gotland

A more direct confrontation could occur as a naval standoff, triggered by NATO’s decision to enforce a stricter blockade on Russian oil shipments. In response, Russia might deploy a convoy of shadow tankers, protected by Baltic Fleet warships, including guided missile destroyers and corvettes, to ensure the security of its commercial vessels.

NATO, perceiving this as a direct challenge to its authority in the region, would respond by deploying its Standing NATO Maritime Group 1 (SNMG1), supported by Swedish, German, and Danish naval assets. Sweden’s Gotland-based surveillance systems would prove instrumental in tracking Russian fleet movements, offering NATO superior situational awareness. As Russian warships approached the Danish Straits, NATO would engage in high-intensity posturing, with both sides conducting simulated attack drills and electronic warfare operations.

The escalation of tensions would be exacerbated by Russia’s deployment of Iskander-M missiles from Kaliningrad, aimed at intimidating NATO forces through precision-strike threats against Danish and Swedish military installations. The strategic role of Germany’s Type 212A submarines would become increasingly pronounced as these assets would shadow Russian vessels, preparing to engage should hostilities escalate further.

A prolonged naval standoff would ensue, marked by heightened alert levels, increased air patrols, and intermittent cyber-attacks on both sides. The crisis would remain in a delicate equilibrium, with neither side willing to fire the first shot but both fully prepared to engage if provoked. This scenario, while avoiding immediate large-scale combat, would push diplomatic efforts to the brink, necessitating high-level negotiations to de-escalate the situation. However, a single miscalculation—such as an accidental missile launch or an unintended naval collision—could precipitate full-scale hostilities.

Scenario 3: Large-Scale Naval Engagement and Blockade Enforcement

The most extreme scenario would escalate from a high-intensity naval standoff to full-scale military conflict. Faced with repeated Russian provocations and increased undersea sabotage, NATO would impose a total blockade on Russian energy exports through the Danish Straits, intercepting and seizing vessels suspected of bypassing sanctions. Russia, viewing this as an existential economic threat, would deploy its Baltic Fleet to forcibly escort shadow tankers through the straits, leading to direct clashes with NATO naval forces.

Hostilities would begin with precision-strike engagements. Russian Kaliningrad-based missile systems would launch coordinated attacks on NATO naval installations and airbases in Sweden and Denmark, attempting to cripple Western response capabilities. NATO, in turn, would retaliate with F-35 airstrikes from Danish and Swedish bases, targeting Russian anti-access/area-denial (A2/AD) systems in Kaliningrad.

The conflict would lead to the deployment of German and Swedish submarines, which would seek to disrupt Russian fleet movements. These undersea assets, coupled with NATO’s superior air power, would effectively cripple Russia’s ability to maintain control over its naval operations. The United States and the United Kingdom would likely enter the conflict, deploying additional reinforcements to the region. The launch of Tomahawk cruise missiles against Russian radar and missile sites in Kaliningrad would neutralise Moscow’s ability to sustain long-range strikes, forcing Russian commanders to reassess their operational viability in the Baltic theatre.

As the engagement escalates, Sweden’s Gotland-class submarines would play a decisive role, targeting Russian surface combatants and further disrupting the security of Russian convoy movements. Meanwhile, Russian forces would attempt to counterbalance NATO’s naval dominance by launching long-range missile strikes from the Northern Fleet, aimed at NATO logistics hubs in Denmark and Germany.

Despite Russia’s determination to secure access to the Danish Straits, NATO’s overwhelming firepower and control of the air and sea would likely result in a decisive defeat for the Russian Baltic Fleet. However, Moscow, unwilling to accept a humiliating loss, might escalate the conflict through the threat of nuclear retaliation, particularly if Kaliningrad faced the prospect of invasion. The intervention of global diplomatic actors would then become inevitable, as the conflict would risk spiraling into a full-scale East-West war.

The United States' Potential Reaction to a NATO-Russia Conflict Over the Danish Straits

A NATO-Russia conflict over the Danish Straits would present the United States with a complex political and strategic dilemma, particularly under a Donald Trump presidency. Given Trump’s historically adversarial stance toward NATO, his isolationist inclinations, and prior interest in Greenland, the U.S. response would likely differ from traditional commitments to European security. Unlike past administrations that consistently bolstered NATO unity and deterrence against Russia, a Trump-led administration would likely prioritize transactional diplomacy, selective engagement, and potential opportunism over firm military commitments.

• A Reluctant Response and Possible U.S. Retrenchment

Trump has long been vocal in his skepticism of NATO, frequently questioning the alliance's financial burden-sharing and suggesting that NATO allies should defend themselves if they fail to meet defense spending targets. This raises the possibility that, in the event of a direct military confrontation between NATO and Russia, a Trump administration might hesitate to invoke Article 5, NATO’s collective defense clause, especially if he views the conflict as primarily a European issue rather than an American one.

Trump’s “America First” doctrine would likely shape Washington’s response in three ways. Firstly, his administration might delay or condition military support on European nations increasing defense spending or making economic concessions favorable to the U.S. Secondly, Trump could frame the conflict as a European responsibility, encouraging NATO members such as Germany, France, and the UK to take the lead rather than committing U.S. forces immediately. Thirdly, his administration might use the crisis as a bargaining chip to extract political or economic advantages from Denmark or other allies, leveraging U.S. military involvement in exchange for favorable trade deals or geopolitical concessions.

• Strategic Opportunism: The Greenland Factor

Trump’s attempts to purchase Greenland from Denmark suggest that a conflict in the Danish Straits could reignite American interest in Greenland, albeit under more aggressive terms. If Denmark was drawn into a military confrontation with Russia, Trump might use the crisis to pressure Copenhagen into granting the U.S. greater military control over Greenland—potentially as a condition for American intervention. This could include expanded basing rights at Thule Air Base or even U.S. territorial claims, citing the need to protect Greenland from Russian incursions.

Moreover, should Denmark suffer substantial military losses, a Trump administration could attempt to use economic coercion—such as leveraging financial assistance or arms sales—to push for an arrangement that benefits U.S. strategic interests in Greenland. This scenario would mirror historical U.S. practices of using security crises to advance territorial and military interests, particularly in strategically valuable regions.

• Limited U.S. Military Involvement with a Focus on Containing Escalation

If the conflict escalates from hybrid warfare into direct naval and aerial engagements between NATO and Russia, the U.S. military under Trump would likely engage selectively rather than comprehensively. This might include:

• Providing logistical and intelligence support without deploying combat forces.

• Positioning naval assets to protect U.S. commercial and energy interests in the North Atlantic while avoiding direct conflict in the Baltic.

• Facilitating arms transfers and financial support instead of deploying large-scale forces.

Trump’s reluctance to engage in prolonged conflicts, particularly in regions where he perceives limited U.S. interests, suggests that any American involvement would aim to prevent escalation beyond the Baltic rather than decisively defeating Russia. His administration could pressure European allies to lead the military response, positioning the U.S. as a strategic supporter rather than a primary combatant.

Conclusion

The scenarios presented span a range of potential escalations, from hybrid confrontations and electronic warfare to the risk of full-scale naval conflict. Throughout these scenarios, Gotland’s strategic importance is undeniable. It remains a critical surveillance and interdiction outpost for NATO while presenting significant military and logistical challenges for Russian forces.

The likelihood of any particular scenario unfolding depends on several key factors: Russia's tolerance for economic hardship, NATO's resolve to enforce maritime restrictions, and the effectiveness of the hybrid warfare tactics employed by both sides. While the United States plays a notable role in shaping the conflict's dynamics, its influence, though important, is not the decisive factor in this region. NATO’s collective action, driven by advanced technology and multinational coordination, would likely provide a tactical advantage.

However, the potential for miscalculation, unintended escalation, and nuclear brinkmanship remains a critical concern. These risks highlight the urgency of diplomatic efforts to prevent catastrophic outcomes. The complexities of this situation extend beyond immediate military engagement, intertwining with broader geopolitical negotiations, particularly regarding the ongoing Russian- Ukrainian conflict. Direct or backchannel negotiations will be crucial in avoiding escalation into a full-scale war that could have far-reaching consequences beyond the Baltic.

¹ The island of Gotland emerges as a focal point in any conflict scenario. Its geographical position at the heart of the Baltic Sea renders it indispensable to NATO’s surveillance and interdiction efforts, as well as to Russian strategic ambitions. Any attempt to control or block Gotland’s military capabilities would likely be a precursor to broader hostilities. Three possible scenarios outline the progression of such a conflict, ranging from a limited hybrid confrontation to a high-intensity naval engagement..