The US paratrooper had a simple message for the people of Haiti. Dressed in khaki, carrying an assault rifle and with the iconic sight of Black Hawk helicopters taking off behind him, he said: "I don't plan on firing a single shot while I'm here. I've been in Iraq three times and I've done enough of that."
The paratrooper was part of the 82nd airborne division from Fort Bragg, North Carolina, a toughened crew of battle-ready fighters accustomed to forming the front- line in many American war efforts.
This time, though, they and their commanding officers – right up to the rank of commander-in-chief, Barack Obama – were keen as mustard to present themselves as helpers and carers, not warriors.
The order has come down from on high that when out patrolling the stricken streets of the city of Port-au-Prince, the paratroopers should have their rifles slung behind their backs. None of that strong-arm brandishing of metal that epitomised the early days in Iraq. "We've been told not to draw attention to our guns," the paratrooper, Sgt David Gurba, said.
By Monday, the US military was visibly out in force at the main airport in Port-au-Prince. Two mammoth C17 military transport aircraft were on the tarmac, one of which landed in front of us, the other unloading jeeps and armoured vehicles.
Providing a solid background hum, the Black Hawks moved in and out of the airport every five minutes, swinging round from the airport to the USS Carl Vinson where 30 of the helicopters were based.
There are 1,700 US troops here, substantially less than the 5,000 or so that had been promised by now.
But in the next couple of days 2,200 reinforcements from the 22nd Marine Expeditionary Unit, backed up by amphibious units, are scheduled to arrive. By mid-week, the US military says, it will have up to 5,000 personnel on the ground and a similar number at sea.
You can't move such numbers of US soldiers into a sovereign country without it looking, slightly inevitably, like an invasion. But that's an impression the Americans are hyper-sensitive about countering. Whoever we talked to made a point of repeating that paratrooper's message.
"I cannot say this more clearly," the spokesman for the commander of the joint task force told us, standing on the tarmac in his military fatigues. "The focus of the American presence on the ground is to help with the humanitarian work. Obama, as our commander-in-chief, has given us the mission of alleviating suffering as much as we can, as fast as we can."
Over at the US embassy on the outskirts of the city, the same message was delivered even more directly: "This is a primary concern of ours," the embassy spokesman told us. "We want the people of Haiti to understand that we are here to help. We are not here to invade or occupy."
The desire to avoid any semblance of invasion is understandable, given the past few years in Afghanistan and Iraq. But there's also a local sensitivity, born of wave upon wave of American interference in the internal affairs of Haiti. Interference that Haitians have put behind them, but that they will never forget.
The Haitian in whose house in Port-au-Prince we are staying – a prominent businessman and generally very pro-America – keeps a cherished machete on his wall. It was used, he explained to me one night, by his grandfather to attack US soldiers during the 1915-1934 American occupation of his country.
"This is a UN-led mission," the US spokesman for the joint taskforce said. "We are just one of many countries that are contributing to the rescue mission."
Such sensitivities perhaps go some way to explain why the American aid effort in Haiti has so far been so cautious. Day seven of the catastrophe, yet wherever we go we are still surrounded by crowds of people living on the streets pleading with us for water. A few miles away at the airport huge quantities of supplies are stacked high in the sun. Under a deal finalised between the heads of relevant parties on Sunday night, US troops will be responsible for securing the incoming supplies at the airport, and then moving them to four central distribution hubs. One of those hubs is at the national football stadium in downtown Port-au-Prince and another at a golf course near the US embassy.
That will free up troops from the UN peacekeeping force in Haiti, so the official line goes, to take charge of the next stage of the process – getting the aid out of the central hubs and to the neighbourhoods. For that purpose the UN has pinpointed 14 distribution locations where it, together with aid groups, will hand out the goods.
The plan sounds neat, thoroughly thought-out, fool-proof. There is only one problem: it is several days late.
Only on Monday were those supplies stranded at the airport beginning to be moved to the four central hubs, and they still need to reach the 14 distribution points, and in turn get given out to the bewildered, sunken, people.
Given that, it's remarkable how patient people appear. In contrast to the lurid accounts of looting and lynching – which has happened, albeit sporadically and at localised flash-points – the Haitians remain strikingly welcoming of the Americans.
"The people have been amazingly peaceful in the circumstances," said Sgt Ryan McGee, one of the paratroopers at the airport, who has been out in the city on security details. "We've seen a little bit of violence in places. But generally wherever we've shown up people have cheered us on. 'USA Number One!'"
On our drive to the airport, we pass one of the myriad piles of rubble where men are still scratching away with pick axes in the now fading hope of finding further survivors. The sight has become so common, so ingrained in the senses, that you hardly notice anymore scenes of astonishing destruction.
And then we did notice. On top of one pile, leading the digging, there was a man with his arms crossed. He was wearing a dusty, crooked Uncle Sam hat.
