The United States just lost a battle to save Taiwan from a Chinese invasion and it's not the first time.
A series of intensive war games are revealing deep-set flaws in its fighting ability.
It's a nightmare, but apparently increasingly likely, scenario: Beijing making good on its threats to invade its island neighbour.
It's a sinister scenario the United States and its allies have become increasingly concerned about as China's military expands and modernises at an extraordinary rate.
Unnamed US defence sources reportedly told The Times that such a conflict was the scenario of a recent intensive war game session conducted by the Pentagon. The results, they say, were "eye-opening".
The scenarios were different and diverse. Some involved clashes in the South and East China Seas. One – the worst-case scenario – was an out-and-out war in 2030.
The US reportedly came out second-best every time.
And that has serious implications for South-East Asia's security.
"The 2020s will see greater risk as China begins to get the capability to challenge the US at sea and in the air (also in space and in cyberspace)," says Australian Strategic Policy Institute (ASPI) analyst Dr Malcolm Davis.
"That could tempt it to make moves in the South China Sea and against Taiwan. The US may not be ready to meet that challenge."
"Every simulation that has been conducted looking at the threat from China by 2030 have all ended up with the defeat of the US," China Power Project director Bonnie Glaser of the Centre for Strategic and International Studies (CSIS) think-tank in Washington told The Times.
The war-games revealed that the US risked "capital losses" even under current circumstances.
Capital is a reference to both capital ships, such as the US Navy's enormous nuclear-powered aircraft carriers, and forward operating bases like those at Guam and Okinawa.
"China has long-range anti-ship ballistic missiles and hypersonic [more than five times the speed of sound] missiles," one source reportedly said.
Dr Davis says this technology gives China the power to keep US military forces at arm's length.
"The main challenge the US faces is sustaining the ability to project military force deep inside China's anti-access and area denial (A2AD) perimeter – which is expanding as the PLA introduces new long-range strike capability," he told News Corp today.
"Carrier-based airpower, in particular, is being challenged."
Supercarriers such as the Covid-19-crippled USS Theodore Roosevelt have been at the heart of US naval thinking since World War II.
Then, they could move swiftly and unseen across the world, launch surprise strikes and quickly retreat out of the range of counter-attack.
Times have changed.
Dr Davis says the immense investment of time, human resources and capital represented by US Navy's supercarriers are offering diminishing returns.
WAR GAME WARNINGS
War-games rarely turn out well. They're usually designed to test ideas and capabilities to breaking point. This is to reveal their strengths – and expose any weaknesses.
But, according to Dr Davis, such exercises also attempt to determine the state-of-play.
"I also think that there is a degree of accuracy and relevance about the reports and their implications," he says.
They represent an attempt by the US to shift its thinking away from the anti-terror wars of recent decades back to facing major power threats.
"A lot of their military capabilities, which excel in attacking low-level non-state threats, don't survive that well against an opponent with advanced anti-access and area denial capabilities," Dr Davis says.
"Yet it takes time and money to reconfigure the US military machine, and China especially is not moving slowly."
To emphasise this point, China last week launched an 11-week combat exercise in the confines of the Yellow Sea.
Both its aircraft carriers – Liaoning and Shandong – will be leading a combined fleet through a series of drills and manoeuvres.
It's not as provocative as it could be. The Yellow Sea is much closer to home than the East or South China Seas.
But its scale and duration are a clear signal that Beijing is increasingly confident it has the strength and endurance to conduct an extended campaign.
FORCE OF HABIT
Previous war-games held over the past decade have exposed several critical flaws in Western military thinking.
The proliferation of mid-range ballistic missiles puts previously distant bases within easy reach.
Another demonstrated how vulnerable long-range tanker aircraft are to attack – leaving strike fighters high and dry. And the helicopter-carrying troopships of the US Marine Corps (and Royal Australian Navy) were shown to be big baskets holding all their eggs.
"Forward bases such as Guam and Okinawa would be attacked at the outset of any military conflict, so probably wouldn't be available for us," Dr Davis says.
Mobile bases such as US Navy supercarriers and Marine Corps assault ships are little better off.
The carrier-borne F-35C has an unrefuelled combat radius of about 1100km. This can be boosted up to 1800km if in-flight refuelling is available.
"But there are logistic challenges sustaining an airborne refueller on station, not to mention the risk of the refueller being shot down," Dr Davis says. "Investment in unmanned refuelling platforms like the MQ-25 Stingray eases this a bit."
But even this is not enough.
"That 1800km combat radius still requires the carrier to penetrate deeply into China's A2AD (area defence) envelope, which now extends out to about 4000km from the mainland," he says.
Which is why supercarriers are at risk of becoming the dinosaurs of the modern era – like the battleships before them.
"Penetrating the A2AD envelope is getting more challenging, and demands devoting more of a carrier battlegroup's firepower to defensive capability rather than offensive punch," Dr Davis says.
"With China now deploying hypersonic weapons that add to the survivability issues for US carriers."
There are alternatives.
"Distributed Lethality – not concentrating so much on big carriers," Davis says, "it is spreading offensive capability across greater numbers of smaller vessels. But the US Navy just recently eschewed that recommendation in a recent report."
Meanwhile, the US Air Force appears to be taking a leaf out of China's book.
"Greater reliance on more long-range strike platforms is another solution, and voices are saying additional investment in bomber capabilities is the answer – a larger B-21 Raider force, adapting B-1Bs to carry hypersonic weapons," Dr Davis says.
"But force modernisations takes time and money, and the risk is that the US will have to cut corners in terms of current readiness and operational ability to fund it."
Australia's air force is taking a different approach. It is instead seeking to repurpose its F-35 Stealth Fighters as 'motherships' for flights of "Loyal Wingmen" drones optimised to tackle high-risk targets at a minimal cost.
"The bottom line is that the US needs to find new ways for its naval forces to survive China's new capabilities," Dr Davis says.
• Jamie Seidel is a freelance writer