France’s first ambassador to America arrived in 1778, when the War of Independence still raged and 10,000 Redcoats still squatted in Lower Manhattan. The US’s oldest ally has shipped officials across the Atlantic ever since, even as France herself was convulsed by three revolutions, two world wars and periodic bouts of German occupation. Yet in September 2021, this 243-year tradition abruptly stopped. At the personal request of President Macron, the French ambassador flew back home from his leafy embassy near the Potomac. To underline its displeasure, the Élysée Palace also cancelled a planned Franco-American gala off Baltimore, celebrating a French naval victory over the UK in 1781.

Everyone now knows the cause of French outrage: submarines. Despite signing a $66bn contract to supply Australia with 12 diesel-electric submarines, France found itself shoved aside by its mightier sister republic. In a secret deal – revealed to the Élysée just hours before it was announced – Australia decided to abandon the French offer in favour of an American alternative. Partnering with the UK, the US plans to sell Australia a fleet of sophisticated nuclear-powered submarines instead. France, for its part, was left with nothing but complaints of its betrayal.

Unsurprisingly, the so-called AUKUS spat has gained much attention: for what it says about the future of Nato, and for how US geopolitical priorities have moved decisively away from the Middle East towards China and the Pacific. Amid the furore, however, fewer pundits have focused on the submarines at its heart. This is unfortunate, especially given the deal is far from the only place where the US is putting underwater warfare at the core of its strategic thinking. Unveiled earlier this year, the SSN(X) promises to be the ‘Generation Attack Submarine’ of tomorrow, with all the tools the US will need to rule the waves until midcentury. And though it’s still in early development, the SSN(X) also hints at what the US Navy will be vying with – and who.

Plumb the depths

In large part, the US’s existing submarine fleet was shaped by the collapse of the Soviet Union. With Moscow humbled and Beijing still an economic minnow, the US’s strategic planners saw their country without any serious rivals. With Pax Americana the order of the day, Washington believed its military could instead focus on less equal threats: tinpot despots, terrorists, pirates. This, at any rate, was the broad thinking behind the Virginia-class submarine. Designed to replace hulkier Cold War predecessors, they were first commissioned in the early 2000s. To put it another way, says Bryan Clark, the Virginia-class obviously had softer targets in mind than the Soviet Baltic Fleet. As Clark, a senior fellow at the Hudson Institute says, the Virginia-class are “economical submarines for the post-Cold War environment” and more lightly armed than their forebears.

“The phenomenal rise of the Chinese navy, including its submarine fleet is no doubt a part of what is shaping the US Navy’s requirements.”

HI Sutton, independent naval analyst


The number of operational submarines currently possessed by China.


This makes the Virginia-class incredibly versatile. Clark notes they excel at everything from delivering commandos to spying on enemy shorelines, ideal for the kind of ‘grey wars’ the US was engaged in during the first years of this century. Yet their relatively small scale also means they’re less suited to direct confrontations with enemy submarines. That could soon become a serious problem, particularly given the ominous ascent of China. “The phenomenal rise of the Chinese navy, including its submarine fleet,” says HI Sutton, an independent naval analyst, “is no doubt a part of what is shaping the US Navy’s requirements”. Fair enough: China now has around 60 operational submarines, up from less than 50 in 1993. More to the point, Beijing has a number of reasons to use its new vessels – not least in its alleged aim of conquering Taiwan by 2027, to coincide with the 100th anniversary of the People’s Liberation Army.

And though China is probably the US’s most serious strategic threat, the Virginia-class also face powerful rivals elsewhere. “The Russian Navy should not be forgotten,” emphasises Sutton. “They too are modernising and are fielding new submarines which are much closer to the US Navy quality. And Russia is building completely new categories of submarine, designed to carry the Poseidon nuclear weapon. These need to be countered.” Clark agrees, adding that Russia’s naval strength also lies in its geography. While the Chinese coastline is relatively accessible to wouldbe interlopers, it would be far harder for the US to secure air and naval supremacy in Russia’s isolated north. Given the country’s Arctic ports, notably Arkhangelsk and Murmansk, still serve as major military hubs, Clark hints the US will need to develop a submarine that can disrupt operations there – even if help from the air force or surface navy weren’t forthcoming.


Read the press releases and the SSN(X) certainly seems ferocious. Enjoying an initial yearly research budget of $98m, it promises to “counter the emerging threat posed by near peer adversary competition for undersea supremacy”. And though US Navy officials are reluctant to comment at this early stage – the first SSN(X) is only expected to slip its moorings in 2031 – what they are willing to admit still sounds impressive. “The SSN(X) baseline design is expected to capitalise on the acoustic and sensor performance, operational availability, and speed and payload capacities of Virginia, Columbia, and Seawolf-class submarines,” explains Rear Admiral Douglas Perry, director of Undersea Warfare Division, N97, at the Naval Operations, US Navy. “It is expected to retain multi-mission capability and sustained combat presence.”

Beyond the military jargon, however, getting to grips with the SSN(X) is rather tougher. As Clark notes, that’s to be expected: the US Navy likely hasn’t decided on a final design itself. All the same, speak to the experts and the broad outlines of the new vessel do become sharper. With its focus on payload and speed, Sutton says the SSN(X) is likely to “excel” at submarine warfare. Clark makes a similar point. Given their role as submarine hunters, he suggests the new vessels will be armed with extra room for torpedoes. That could also be complemented by hypersonic missiles. Trialled by the navy in 2020, their remarkable speed (over five times the speed of sound) would theoretically allow the SSN(X) to hit targets before they even had time to react. More broadly, the SSN(X)s will probably be quieter than their predecessors, all the better to attack enemy vessels without being spotted. Like the 52 attack submarines already in the US repertoire, they’ll partly achieve this stealthiness by relying on nuclear reactors.

Aside from boasting practically unlimited range, nuclear-powered submarines are also much quieter than diesel alternatives – the lack of nuclear-powered vessels in the Franco-Australian deal might explain why Canberra reneged on the offer. At the same time, the future vessels could come with even more sophisticated equipment. Though both Clark and Sutton both emphasise that the idea is still very much under development, that could extend to so-called ‘sailless’ features. This essentially means the SSN(X) would dispense with the ‘sail’ – or ‘fin’ – normally sticking out at the top. That would make them even more discrete and aerodynamic – though would also mean the crew wouldn’t have an easy way of leaving the vessel above the waterline.

Dire straits

Whatever the SSN(X) ultimately becomes, its role in the future of US naval operations is clearer. Sutton says it’ll be “a vital element” of US strategy, both in Asia-Pacific and elsewhere. Clark concurs, especially when it comes to the question of China. If tensions in the Taiwan Strait ever boil over, he says submarines like the SSN(X)s would be crucial in sinking Chinese troop transports before they ever reached Taipei. That’s doubly true given Chinese attempts to combat the effectiveness of the US’s existing fleet. Among other things, Beijing plans to put sensors at strategic chokepoints on the ocean floor, aiming to catch the Virginias before they can do any damage (or anyway gain useful information on Chinese troop movements). That’s bolstered by patrol aircraft and warships –and even low-orbit satellites specifically designed for spotting enemy vessels underwater.

The existing Virginia-class submarines can probably dodge some of these traps already, particularly given how they’re designed. Built to limit the emission of acoustic and magnetic signatures, they’re already hard to spot. Even so, the SSN(X) are likely to be even quieter, only confirming the US’s status as the predominant sea power in the Pacific. And if anything, the importance of these vessels to Washington planners can be seen in the fact that they’re avowedly bipartisan. Unlike practically everything else in the US today, investment in future submarines has been supported by the last three administrations, including that of Donald Trump.

“The SSN(X) baseline design is expected to capitalise on the acoustic and sensor performance, operational availability, and speed and payload capacities of Virginia, Columbia, and Seawolf-class submarines.”

Rear Admiral Douglas Perry, US Navy


The number of attack submarines currently possessed by the US.


Beyond things like sailless design, meanwhile, there’s a possibility that the submarines of tomorrow will include even more outlandish kit. One of the most curious is automation, whereby submarines patrol the depths but are piloted by crew somewhere else. Sutton is careful to warn that “we are a long way from seeing uncrewed submarines replacing” manned vessels – but does say they could soon conduct missions closer to shore, with regular attack submarines acting as “mother” to a brood of torpedo-armed kids. Assuming they finally arrive, perhaps President Biden should consider offering a few to his Gallic friends across the sea. A second submarine snub is surely more than even this oldest of alliances could bear.