The main mission of the US Army flotilla now sailing toward Gaza is to build a floating pier that will help ships offload desperately-needed humanitarian aid. But the task force also serves a secondary purpose: it’s practice for a critical combat operation – one that could help US forces to roll back Chinese advances in the event of a war over Taiwan.

Taiwanese soldiers apply camouflage face paint during a training exercise. The island democracy faces imminent invasion by Communist China.

The Joint Logistics Over-the-Shore pier system, or JLOTS, is a Lego-like suite of floating metal piers and ramps that can connect virtually any ship to virtually any beach. While the Pentagon is sending five 273-foot US Army landing craft to begin building the pier, the final components will sail aboard the 951-foot transport ship Roy A Benavidez, which belongs to the US Navy-administered Ready Reserve Force.

It could take weeks to ship the pier components and days to assemble them. But once the pier is ready, it should be able to move – from sea to shore – 2,000,000 meals per day, according to the Pentagon.

The Pentagon has deployed JLOTS before, perhaps most notably to Haiti following the devastating earthquake in that country in 2010. But it has never deployed it in a major war.

That could change – and soon – if China makes good on decades of threats and launches an invasion of Taiwan. If the People’s Liberation Army succeeds in occupying Taiwan’s island strongholds in the Taiwan Strait as a prelude to landing on Taiwan itself, counterattacking US forces could face a serious dilemma: how to land their own people and equipment in what amounts to a counter-invasion of mainland Taiwan and its island outposts.

Historically, US forces would force their way ashore aboard US Navy amphibious ships. But the US fleet has lost faith in its traditional amphibious capability as enemy beach-defenses stiffen with increasingly deadly anti-ship missiles. Lately, the US Navy has been decommissioning amphibious ships faster than it commissions them.

But JLOTS endures. And it gives the Pentagon options.

“JLOTS is a critical joint capability that enables US forces to enter a land area from sea despite insufficient port infrastructure,” Joseph Tereniak, a US Army officer, wrote recently.

It’s not that Taiwan doesn’t have great ports: it does. But if Chinese forces control those ports as US and allied forces counterattack, the Americans and their allies will need some other way of moving heavy equipment over the beaches. “Potential adversaries will attempt to deny access to fixed ports,” US Army officer Tom Clady wrote in 2013. “Seabasing provides a viable alternative to project forces.”

The problem with JLOTS, of course, is that it’s a big floating target that takes days to set up and, even when it’s working perfectly, is a delicate piece of maritime clockwork. The speed at which soldiers and sailors can build the pier – and rebuild the pier in the event of an enemy attack – could make the difference between victory and defeat.

Back in 1996, a naval official named Harold Workman warned of a “lack of training, and therefore diminished proficiency levels,” that could doom JLOTS ops in wartime. It’s not clear that, nearly 30 years later, the US Army and US Navy have solved the training problem. JLOTS just doesn’t get used very often in a truly stressful environment.

Gaza is nothing if not a stressful environment, with Israeli forces relentlessly bombarding cities and towns and even hospitals and Iran-backed militants – including the Houthis in Yemen – lobbing drones and missiles at commercial and naval vessels in the region.

US president Joe Biden announced the Gaza pier operation during his annual state-of-the-union address to the US Congress on March 7.

“I’m directing the US military to lead an emergency mission to establish a temporary pier in the Mediterranean on the Gaza coast that can receive large ships carrying food, water, medicine and temporary shelters,” Biden said.

“No US boots will be on the ground,” Biden added. They’ll only be on the pier.

Increasingly impatient with Israeli prime minister Benjamin Netanyahu, Biden is counting on the US Army’s logistics fleet not only to save Gazan lives, but also to signal his – and America’s – opposition to continuing Israeli aggression. As a bonus, the fleet will be practicing a unique military skill: the construction of a temporary port.

“This temporary pier would enable a massive increase in the amount of humanitarian assistance getting into Gaza every day,” Biden said.

It would be crass to think of the coming humanitarian JLOTS deployment primarily as practice for war. But it would also be naive to pretend American soldiers and sailors won’t benefit from building a pier from scratch in a war zone. Even if that war doesn’t directly involve US troops.

Those Americans just might be ordered to build the pier again in the waters around Taiwan, while Chinese missiles rain down.