Approaching from the Hawaiian coast, the mosquito-shaped helicopter buzzed around this guided-missile cruiser twice before swooping towards the landing pad. The navy crew on the deck crouched, the helmeted faces betraying more than routine concern as the aircraft, flown by a pilot who had never before alighted upon a ship, hovered a foot off the tarmac and then set down with a thud.
The sailors' trepidation was prompted by three words painted in black block letters on the drab olive fuselage: United States Army.
The US army, which fights on terra firma, does not usually land its helicopters on ships - the domain of the navy and the Marine Corps - but these are not usual times in the US military.
As US President Barack Obama winds down the army-centric war in Afghanistan, Pentagon leaders are seeking to place the air force, navy and marines in dominant roles to counter threats in the Asia-Pacific region, which they have deemed to be the nation's next big national security challenge.
Fearful that the new strategy will cut its share of the defence budget, the army is launching an ambitious campaign to transform itself and assert its relevance in the Pacific. And that, in turn, is drawing the army into a fight - with the marines.
Calculating that there are only slim chances of the army fighting a big land war anywhere in East Asia other than the Korean peninsula, the new top army commander in the Pacific, General Vincent Brooks, wants his forces to respond more quickly and effectively to small conflicts, isolated acts of aggression and natural disasters. Doing so, however, has traditionally been a challenge for the army, which bases most of its soldiers assigned to Asia in Hawaii, Alaska and Washington state. To overcome what he calls "the tyranny of distance", Brooks is trying to make his forces more maritime and expeditionary.
To cut travel time and increase regional familiarity, he is seeking authorisation to send key elements of a US-based infantry brigade to Asia and keep them there for months at a time, moving every few weeks to different nations to conduct training exercises. The rotating deployment amounts to the first proposed increase in US forces in Asia in years.
Brooks said he wanted "a capable force that can respond to a variety of contingencies" - rapidly. "Forces that are already in motion have an advantage in responding," he said.
The initiative, which Brooks is calling Pacific Pathways, is also an opportunity to recast the army's image in Washington, yielding television images of soldiers - not just marines and sailors - responding to typhoons and cyclones.
To the Marine Corps, however, Brooks is committing the military equivalent of copyright infringement. Marines regard themselves as the nation's first - and only - maritime infantry force. They have troops in Asia that are not tied down in Korea - three infantry battalions, an aviation wing and a full logistics group based in Okinawa, Japan - and, they note, they have an expeditionary unit that sails around Asia to conduct bilateral exercises and respond to crises. Those marines were among the first to respond to Typhoon Haiyan in the Philippines last month.
"They're trying to create a second Marine Corps in the Pacific," said a marine general, speaking on the condition of anonymity. "To save their budget, they want to build a force the nation doesn't need."
The army-marine fight has profound implications for both services.
If Brooks succeeds, army leaders would lay claim to a new strategic narrative and gain a powerful argument to stave off additional rounds of personnel cuts, while the marines could face an existential crisis without their exclusive expeditionary status. If Brooks fails, the army, which is planning to shrink from 540,000 to 490,000 soldiers by 2017, could become even smaller.
Both sides see the battle in winner-take-all terms: the administration's strategy has all but rejected the sorts of troop-intensive counterinsurgency campaigns waged by the army in Iraq and Afghanistan. Instead, they call for a focus on Asia to counter China's growing influence.
Planning documents envision not a head-on war with China but the need to be able to confront Chinese efforts to control shipping lanes and seize disputed territory with air and naval power and an agile ground force.
"There is no doubt about the need for expeditionary, amphibious troops," a senior Defence Department official said. "The question is whether we need the army to provide that capability."