Should a war erupt with China over Taiwan, many observers seem to think that Europe would be largely irrelevant as far as the actual fighting is concerned. Those who share this opinion typically point to Europe’s reluctance to confront China or a lack of meaningful military capabilities to bring to the table. Or they prefer Europe simply mind its knitting and focus on the Russian threat, which is much closer to home, and would free up the United States to concentrate on China.
We have a different perspective.
A war over Taiwan that draws in the United States and its Asian allies would likely become a bloody, drawn-out fight that geographically expanded beyond the Western Pacific. The strategic repercussions of a local conflict that assumed global characteristics, including fighting on the world’s oceans, would likely compel European military involvement in one form or another.
To advance this debate, we set a high bar by focusing on high-end conventional combat. We lay out the conditions that could incline Europe to get involved militarily. We then test the various direct military contributions that Europe could make.
Far from being strategically sidelined in the event of war, Europe could prudently offer operationally relevant capabilities, possibly tipping the scales in favor of an allied campaign to defend Taiwan. Nuclear submarines would likely be the most valuable asset European countries could contribute.
The Debate
In recent years, there has been a flurry of wargames and table-top exercises trying to ascertain the likelihood and possible consequences of a potential People’s Republic of China attack on Taiwan. These exercises have focused primarily on unpacking alternative scenarios, including blockade, intensified hybrid attacks, seizure of offshore islands, full invasion, and so forth — and discussing what they may entail for the United States, Japan, Australia, and other relevant regional powers. Comparatively less attention has been paid to the implications of a war over Taiwan for Europe, or Europe’s potential role therein.
To be sure, some recent analyses have pondered on such factors as the legal basis for a possible NATO response to a war over Taiwan, the implications of a Taiwan war for U.S. capability requirements and NATO’s posture in Europe or how the European Union can help prevent an aggression through diplomatic engagement or sanctions. More recently, others have pointed to Europe’s potential contribution to a broader arsenal of democracy. As European defense spending continues to pick up, Europeans could indeed help supply munitions, drones, and other relevant systems to Taiwan, the United States, or Japan, and thus indirectly assist a broader allied effort in defense of Taiwan. They could also help with other critical non-military goods such as energy supplies and raw materials, even if the logistical challenges of supplying Taiwan are admittedly much more acute than in Ukraine.
Most discussions on Europe’s potential contribution to Taiwan’s security focus on peacetime and highlight the non-military and indirect nature of European assistance. This is understandable. First off, Europeans are divided and a bit wobbly on China. While China’s image in Europe may have taken a hit in recent years, going to war with Beijing over Taiwan might be a bridge too far for some. Second, European military capabilities are scarce. And, in the event of a war over Taiwan, such capabilities would likely be devoted to shoring up deterrence in Eastern Europe, especially as the United States turns its attention to the Indo-Pacific. In fact, both Washington and its Indo-Pacific allies may actually encourage Europeans to focus on plugging force gaps in Europe so as to free up as much U.S. strategic bandwidth as possible in the Indo-Pacific.
Undeniably, Europe could wield other coercive tools, such as the threat of sanctions, to influence Beijing’s cost-benefit calculation on whether to invade Taiwan. It is also true that Europeans are likely to prioritize threats closer to home, particularly given the salience of Russian revisionism. That said, there are good reasons to believe that the global spillover effects of a cross-strait war could radically shift Europe’s calculus. Therefore, it is sensible to examine the conditions that could overturn Europe’s prevailing preferences and to assess the kinds of direct military contributions that Europeans could offer in the event of conflict.
Under What Conditions Would Europe Fight for Taiwan?
Arguably, Europe’s response to a war over Taiwan would be significantly conditioned by at least five sets of interrelated factors: context, length, the nature of U.S. involvement, geographical scope, and timing.
The first condition relates to the broader strategic context. Does a war over Taiwan break out in isolation, or while there is an ongoing war — or credible threat of war — in Europe? Would Russia use the distraction of a Taiwan war to strike or double down on aggression in Europe? Relatedly, would Russia directly or indirectly assist a Chinese attack on Taiwan? A war in Europe would no doubt significantly constrain the ability of Europeans to engage in a war over Taiwan, at least militarily. Conversely, a multi-theater or global war could incentivize European military engagement in the Indo-Pacific.
The second condition is length. Would a war over Taiwan be short, or long and protracted? Indo-Pacific Command’s “hellscape” concept and Taiwan’s own total defense concept stress the importance of ensuring the war isn’t quickly lost by disrupting the Chinese military’s operational tempo to buy time for a more organized — and collective — response. The longer the war, the higher the chances that European countries will have an opportunity to contribute to Taiwan’s defense.
The third condition has to do with the nature of U.S. involvement. Would the United States provide significant but indirect assistance to Taiwan, or would U.S. forces engage the Chinese military directly? This is a critical question for Europeans, who have an alliance with Washington (though confined to the Euro-Atlantic area) and see the security of the United States and that of Europe as indivisible.
A fourth and critical factor, which is very much related to the nature of U.S. involvement, has to do with the geographic scope of the war. A contingency confined to Taiwan’s offshore islands or main island is not the same as a broader Sino-American war spreading across the first and second island chains, and into the Indian Ocean.
The fifth factor relates to when the war breaks out, i.e., whether in 2027 — a date often noted in intelligence and expert estimates — or a decade from now. If we assume that European military spending will continue on an upward trajectory, Europeans would be in a position to provide a more significant military contribution in 10 years than in two.
There is growing consensus that a great-power war between China and the United States would produce profound disruptions that span the globe. It is therefore likely that a cross-strait war that drew in the United States, that went long, and that expanded beyond Asia would compel European intervention, even if it took place in the next five years and even if Russia menaced on Europe’s eastern front. It is thus useful to sketch the attributes of such a war to map out where Europe’s contributions might be most efficacious.
What Are the Pathways?
There are various pathways to a widened conflict over Taiwan that draws in Europe. It is possible that Chinese attempts at coercion short of war either fail and compel Beijing to escalate further, or backfire and spur third-party intervention. It is also possible that a military assault confined exclusively to Taiwan nevertheless spirals into a wider regional war. Another possibility is that Beijing would start a war that targeted U.S. and allied military forces and bases at the outset to level the playing field and to seize the battlefield initiative. China may even threaten the American homeland with cyber and other kinetic weapons against critical infrastructure.
We do not render judgments about the likelihood of these pathways. The point is that China could find itself in an expanded conflict even if its initial strategy was precisely meant to avoid one. Moreover, our aim is to identify some constant features of an expanded war that would be most relevant to how Europe considers its military role should it choose to help resist Chinese aggression.
To fight and win a cross-strait war, Chinese military doctrine specifies three types of campaigns, namely an air and missile campaign, a blockade, and an amphibious invasion against Taiwan. These operations would not necessarily be mutually exclusive. For example, a bombardment and a blockade could precede an invasion. To maximize its chances of success, the Chinese military would seek to seize local command of the air, seas, and other domains and deny those same commons to the enemy. Its land-based missiles, airpower, and naval forces as well as a thicket of modern air and missile defense systems would support a range of operations against the island. The Chinese military’s anti-access/area denial network would be densest and most lethal to hostile forces around Taiwan, the Taiwan Strait, and the island’s surrounding air and sea spaces.
In a hypothesized regional war against the United States and its allies, the Chinese military would mount a forward defense by targeting regional bases along the first and second island chains and rendering the approaches to mainland China hazardous to the enemy. Chinese military doctrine and the large-scale deployment of long-range strike capabilities suggest that Chinese military commanders would conduct air and missile bombardment against major bases, such as Kadena airbase, Yokosuka naval base, and facilities located on Guam. Shore-based airpower, submarines, and land-based anti-ship missiles would contest access to and operations from the Philippine Sea. Defenders in southern China, on Hainan Island, and on the manmade Spratly Island bases would threaten passage through and movement in the South China Sea. There is strong evidence that Beijing would challenge allied undersea operations there.
Beyond the Western Pacific, the mostly likely theater of hostile contact would be the Indian Ocean, where the Chinese navy has kept a rotating naval flotilla since 2008, and where China maintains a permanent military base in Djibouti. The Chinese navy’s globalizing posture and its doctrinal intent to stage a global presence suggest that horizontal escalation that leads to a multi-theater conflict is a distinct possibility. Mike McDevitt suggests that if a cross-strait war involved the United States, the conflict would likely escalate rapidly into a global naval war, with the U.S. Navy and Chinese navy clashing wherever they met around the world. As Aaron Friedberg further observes, the Chinese navy’s relative weakness in the Indian Ocean might tempt it to “get in the first blow” to knock the United States off balance and thereby compel U.S. forces to divert resources from the central front in the Pacific to that secondary theater.
China’s military campaigns would be waged by the largest navy and the largest conventional missile force in the world, the largest air force in the region, and a massive industrial base located near the frontlines. China thus possesses the mass to inflict heavy damage at the outset, to “flood the zone” in certain areas close to the mainland, to sustain operations, and to absorb significant losses without these triggering strategic paralysis.
Implications for Europe
A widened conflict of the kind depicted above would shape European decisions about how they could make the best use of their scarce military resources. Consider, for illustrative purposes, how the war would intersect with high-end combat systems, such as fighters and warships, that Europe could contribute to the fight.
The immediate zone of conflict surrounding Taiwan and the Western Pacific area that covers U.S. and allied bases on the first and second island chains would be highly contested. China’s anti-access/area denial network would thus place an extraordinary premium on survivability. Generally, large-signature platforms, such as major surface combatants and non-stealthy airframes, would be vulnerable when operating within range of China’s reconnaissance-strike complex. This explains arguments for keeping high-value American assets, such as carrier strike groups, east of the second island chain.
Even stealthy F-35 fighters, although expected to be widely available in European air forces, might not be suitable for such a deadly environment. Owing to their limited range, the F-35s would rely excessively on regional airbases located well inside the Chinese military’s weapons engagement zone, and on vulnerable large-signature aerial refueling tankers to conduct operations. In the widened war hypothesized here, China will have attacked and possibly knocked out major airbases along the first island chain upon which F-35s would depend. Moreover, the fighters might be badly needed in Europe and are already in service among allies in the Indo-Pacific.
Extra-regional theaters like the Indian Ocean, by contrast, are largely beyond the reach of China’s land-based anti-access/area denial network, although the Chinese navy maintains a presence there and theater-range missiles, such as the DF-26, could in theory threaten shipping in the Bay of Bengal. As such, Europe’s carrier strike groups and surface action groups could be quite effective in performing escort missions and conducting interdiction and anti-submarine warfare operations across wide swathes of the Indian Ocean, a major thoroughfare for allied power projection, and a region where France and the United Kingdom have overseas territories and bases.
Beyond exquisite systems, Europe would likely be well positioned to offer lower-end capabilities tailored to the operational environment. For example, special operations forces, missile-armed fast attack craft, and other tactical units designed to better elide China’s sensors could be employed for the close-in fight along the straits and narrow seas of the first island chain. The bottom line is that the warfighting scene, both near and far from China, offers parameters for European leaders to make informed decisions about what platforms to rule out and what capabilities could be offered to join the fight.
Submarines as the Most Decisive European Contribution
Among the various exquisite systems that Europe could offer, its undersea capabilities, particularly nuclear-powered attack submarines and, to a lesser extent, diesel-electric attack submarines stand out. European navies boast a combined fleet of 66 submarines, among which are 7 British Astute- and 6 French Barracuda-class nuclear-powered attack submarines. The mobility, range, and endurance of nuclear-powered attack submarines would allow Britain and France to swing the attack boats from European waters to the Indo-Pacific, even if the persistence of the Russian threat in the North Atlantic may limit their availability. It is also worth noting that the weeks it would take for these submarines to reach their stations in Asia, if they began their transits in Europe, mean that the warring sides have likely settled into a protracted war.
A network of homeports and support facilities, especially those located outside the Chinese military’s weapons engagement zone, such as Hawaii and Diego Garcia, would be available to European nuclear-powered attack submarines. Although Guam and Yokosuka would almost certainly come under attack in a widened conflict, they may offer some degree of support in wartime. Moreover, starting in 2027, Australia’s HMAS Stirling will be home to Submarine Rotational Force-West, comprising forward-staged U.S. and U.K. nuclear-powered attack submarines. In other words, leaning more on submarines would build on existing infrastructure and ongoing initiatives, thereby reducing duplication of effort.
The submarines’ greatest strength is their survivability, which will be especially superior to their naval surface and air counterparts for the foreseeable future. Aside from the most contested areas, such as China’s coastal waters, they will likely be able to operate with near impunity inside the Chinese military’s weapons engagement zone. Short of some revolutionary breakthrough that rendered the seas transparent, competent undersea forces will be very hard to find.
European submarines would exploit China’s longstanding structural weakness in anti-submarine warfare — one that, admittedly, China has begun to address. Nevertheless, American and allied undersea forces will likely be unmatched for at least another generation. Indeed, the promise of enduring underwater superiority was one reason behind Australia’s big bet on a nuclear-powered submarine force under the AUKUS framework.
Perhaps most important, European nuclear-powered attack submarines would meet two urgent American needs. First, the U.S. military, including its submarine force, has descended into a capacity trough that will run through the remainder of the 2020s into the early 2030s. Owing to bad political decisions, fiscal constraints, and an atrophied industrial base, the U.S. Navy has been unable to maintain the production rate necessary to meet its force structure target. As such, the silent service will field an older and smaller force than it has ever done in decades. Tellingly, although the U.S. Navy estimates that it needs 66 submarines to fulfill its global missions, it currently has about 49. This fleet is expected to dip further to 47 nuclear-powered attack submarines in 2030 — the bottom of the trough — before clawing its way back to 50 boats in 2032 and rising slowly to 64 or 66 submarines three decades hence. Relatedly, and critically, U.S. allies in the region thus far lack this capability.
Yet, such an undersized fleet will be expected to shoulder a heavy burden in war. American submarines will be tasked to hunt down China’s aircraft carriers and surface combatants as well as the amphibious ships crossing the strait, conduct strikes ashore against various land targets, trail Chinese strategic ballistic missile submarines, and sink enemy submarines. Those that have exhausted their weapons would need to return to port to rearm, taking them temporarily out of action. Despite their tactical superiority, losses will likely be inevitable.
Given the enormous demand for submarines, allied contributions through nuclear-powered submarines would do much to offset the operational load. Although the Japanese military boasts a fleet of modern submarines and would play an important role in a cross-strait conflict, its diesel boats lack the kinds of qualities, such as endurance, that nuclear-powered submarines possess. European attack submarines would thus add flexibility and options — in addition to numbers — to the coalition campaign.
Second, as noted above, a war over Taiwan could quickly spread to the Indian Ocean. Given the decline in numbers, it is unclear the extent to which the U.S. military can adequately deal with a secondary front where China might be inclined to employ its expeditionary maritime forces as a diversion. Moreover, U.S. decision-makers have not had to think seriously about waging a multi-theater war since the height of the Cold War and it is doubtful that they have relearned the atrophied skills of fighting a globalized conflict against a peer adversary. In short, the United States will likely need all the help it can get in the undersea domain.
If European submarines were deployed to the Indo-Pacific in a major conventional conflict, they could be used to defend the wide perimeter along the exterior lines of the first island chain. They could keep open the main access routes into the theater of operations for U.S. and allied forces while bottling up the Chinese navy within the first island chain. Acting as gatekeepers, European submarines could intercept Chinese surface and submarine forces seeking to break out of the South China Sea through the Malacca Strait in the west, the Luzon Strait in the east, and everywhere in between.
The attack boats could also play offense. Armed with long-range land-attack cruise missiles, the European nuclear-powered submarines could launch strikes against Chinese targets, including its bases in the South China Sea, from standoff distances. To balk attempts by China to open a new diversionary front, the boats could sever the lines of communication connecting China’s expeditionary forces in the Indian Ocean from their home bases on the mainland, thereby isolating them from reinforcements and resupply. The submarines could also hold at risk China’s access to and use of the critical sea lanes so essential to fueling its economic engine. Indeed, such threats would exploit a deeply embedded Chinese psychological fear of being cut off from the seas.
Some of these potential missions, such as enemy interdiction across the vast expanse of the Indian Ocean, would be capital-intensive, requiring mass to fulfill. As such, Europe’s contribution should conform to the number of attack boats that it could realistically deploy to the Indo-Pacific. Assume that European navies follow a four-to-one availability ratio, meaning that the routine cycle of deployment, extended overhaul, and workups requires four submarines to keep one ready for action at any given time. Assume also that submarines going through exercises, training, and inspections can be surged in an emergency. If so, then a combined Anglo-French fleet could in theory dispatch three to four nuclear-powered attack submarines to Asian waters in wartime.
This may appear to be a limited contribution that would be inadequate to tilt the correlation of forces, but several choices would sustain the operational value of nuclear-powered European submarines. First, the attack boats could fight alongside surface fleets in clearing the seas of threats. Current and future European warships could also combine their firepower with undersea forces to launch cruise missile salvoes against land targets. There is precedent for this: HMS Triumph, a Trafalgar-class nuclear-powered submarine, together with the U.S. Navy’s two destroyers, two fast-attack submarines, and a cruise-missile-armed submarine, fired more than 120 missiles to take down Libya’s integrated air defenses during Operation Odyssey Dawn in 2011.
Second, British and French nuclear-powered submarines could be augmented by diesel-powered and air independent- powered hunter-killer submarines in service with other European navies. Although less versatile than their nuclear brethren, demand for such boats from other oceangoing navies suggests that they would be tactically relevant in places like the Indian Ocean. Indeed, the French Scorpene, the German Type 214, and the Spanish S80 submarines are being — or have been — considered by the Australian, Canadian, and Indian navies. To compensate for the long transit times necessary to reach the Asian theater of operations, these boats could be forward staged on a rotational basis at bases in Western Australia and Diego Garcia where facilities are equipped to support them. Thus, a core of Anglo-French nuclear-powered attack submarines combined with other European diesel-electric attack submarines could generate the numbers necessary to make a difference in wartime.
Third, insofar as numbers define the mission, the European nuclear-powered submarines could be dedicated to chokepoint defense around geographically confined bottlenecks like those along the Indonesian archipelago. A more sedentary gatekeeping role would ease the demand for more hulls in the water and might be better suited for a small fleet of nuclear-powered submarines, if it were to fight without the help of other assets. In this regard, even a few exquisite systems could have an outsized impact on the enemy’s calculations by dissuading them from assuming certain risks in the first place. Fears of being ambushed by lurking European submarines could convince China’s navy not to transit certain straits or to take time-consuming detours.
Whatever roles that British and French nuclear-powered submarines might play, from perimeter defense to strikes ashore, these submarines would likely help advance allied burden-sharing. They could mitigate or neutralize threats that, if unaddressed, could divert and tie up scarce American resources. Put another way, European boats would enable the United States to concentrate its efforts on the main fight near Taiwan and on other priority missions elsewhere. If the U.S. military were heavily committed in the central front around Taiwan, easing painful trade-offs between theaters and between sub-theaters may be one of the most salutary contributions that Europe could make to this hypothetical war effort.
Follow the Logic
Although there is a strategic and operational logic for Europe to make a meaningful military contribution to a war over Taiwan, the diversion of scarce resources, such as nuclear-powered submarines, will likely be a significant undertaking, requiring forethought and preparations. Defense planners would need to consider calculations of acceptable risk on the home front should submarines be surged to Asia. After all, Russia still boasts a formidable undersea force that Europe would need to contend with, especially if Moscow were to exploit the opportunities presented by an America engaged in large-scale fighting in Asia.
Access agreements and arrangements with allies and partners would need to be established in advance of a crisis or war. Indeed, routine peacetime submarine deployments to the Indo-Pacific might help to shore up deterrence. Europe would need to devote intellectual capital to develop concepts of operations, roles and missions, a proper division of labor, interoperability with allied undersea forces, water space management to avoid fratricide between allied submarines operating in close quarters, and so forth. Should Europe heed this logic, then it should get to work now.
Luis Simón, Ph.D., is director of the Centre for Security, Diplomacy and Strategy at Vrije Universiteit Brussel, and director of the Brussels office of the Elcano Royal Institute.
Toshi Yoshihara, Ph.D., is senior fellow at the Center for Strategic and Budgetary Assessments in Washington, D.C.
This commentary was developed as part of the Bridging Allies initiative, led by the Centre for Security, Diplomacy and Strategy of the Vrije Universiteit Brussel.
Image: U.K. Ministry of Defence via Wikimedia Commons
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