"We could lose against North Korea".
It's not something star-spangled US powerbrokers would want to hear.
Nor is it easy to comprehend, given the highly visible technical advantage US air, naval and ground forces enjoy over Kim Jong-un's largely eclectic mix of equipment, reports News.com.au.
But according to retired Lieutenant General Jan-Marc Jouas, numbers have a quality of their own.
And the former deputy commander of US Forces in Korea warns that when it comes to US and allied forces in the region, scratch the surface and things may begin to fall apart.
His leaked letter to members of Congress comes shortly after US Pentagon officials warned it would take a ground invasion of North Korea to destroy its growing nuclear arsenal.
And US President Donald Trump has repeatedly left open the option of open warfare with Pyonyang, threatening it with 'total destruction' if forced to defend South Korea or Japan.
US troops "are vastly outnumbered by North Korean forces, as well as [allied] forces that will conduct the overwhelming majority of the fighting", General Jouas writes in a leaked letter to members of US Congress.
"Unlike every conflict since the last Korean War, we will not be able to build up our forces prior to the start of hostilities."
Any wave of North Korean troops spilling over the 38th Parallel demilitarised zone would be like a relentless tide - even if much of their weaponry is truly antique.
And the popular image of small bands of heavily equipped, thoroughly trained and well-supported allied troops stemming that tide is not likely to hold up.
Many US combat jets and helicopters are themselves so old they've been falling out of the sky.
The sailors of the US Pacific fleet have been pushed so hard for so long their morale - and performance - has already collapsed. And the ground troops - no matter how good their gear - don't have the supplies or reserves to support a sustained fight.
Put simply, ammunition and spares for advanced weapons are expensive. Which means there's not a lot of it laying around.
General Jouas says there are about 28,500 US troops stationed in South Korea. Even when fighting with the much larger South Korean army, this figure is dwarfed by that fielded by Kim Jong-un - even if mostly poorly trained and equipped.
And he warns any attack on North Korea - be it a 'surgical strike' targeting nuclear facilities or Kim Jong-un himself - would almost certainly spur an all-out war.
In the know
While now retired, Jouas cannot be accused of being an armchair general.
From January 2012 to December 2014, Jous was at the heavily involved in redrawing allied plans to counter any possible attack from North Korean forces on the South.
Opposing him was a army of 1.1 million men organised into 19 combat units drawn from nine infantry corps, four mechanised corps, one armoured corps and one artillery corps.
More than half these forces - particularly when it comes to armour and artillery - is positioned near the border.
"This threat was the most dangerous I'd faced since the end of the Cold War, and planning for it the most challenging problem I'd encountered in my 35-year career," he writes.
The biggest challenge is for the forces on the ground to be able stand the weeks to months necessary for reinforcements - and fresh supplies - to arrive.
It's a scenario where allied technological advantages could be negated by superior numbers.
While there are plans for reinforcements to be rushed into place from advanced bases such as Guam and Okinawa, General Jouas warns these "may well find their bases subject to attack by conventional or chemical weapons, which will further delay their entry into the war".
And as fresh troops rush to get in, many others would be desperate to get out.
"An enormous casualty and evacuee crisis will develop and include over 100,000 non-combatant Americans, many of who will turn to US forces to get them off the peninsula," he says.
The result would be chaos.
Too many targets
The opening moments of any battle would be violent in the extreme, General Jouas warns.
Thousands of artillery pieces are arrayed along the North Korean side of the border, aimed at the South Korean capital of Seoul as well as vital infrastructure, facilities and bases.
In the capital alone, 25 million civilians would be at risk.
The bombardment by North Korea's artillery, rockets and missiles would be brutal.
General Jouas warns there are so many, allied aircraft and helicopters would need "days" to hunt them down and destroy enough to reduce their impact.
But they may not have that long before their own bases were threatened by advancing troops.
US Democrat Congressman and former US Air Force officer Ted Lieu told Newsweek the letter was a clear warning of the challenges military forces faced against North Korea.
"(We) can't just send over troops and equipment right now because that would provoke a North Korean attack," Lieu said.
"It would take many days to get rid of North Korea's artillery and all their other weapons. In the meantime, a lot of people are going to die."