It is an iconic image seared into the brain of every American defence policy-maker: helicopters soaring from the roofs of government buildings in Saigon, bringing with them US Army officials, ‘at-risk’ Vietnamese civilians, and members of the diplomatic corps. The year was 1975, and the Vietnam War – launched ten years earlier – had ended in bitter defeat. As nations across Asia fell to Communist insurgencies, the so-called Operation Frequent Wind marked a potent symbol of America’s failure to prevent South Vietnam from falling into the sphere of the Soviet Union.

The US withdrawal from Afghanistan was, to put it mildly, a less acrimonious affair. In 2012, NATO and its partners had agreed that allied forces would withdraw from the country at a slow pace during the subsequent two years.

In 2010, the Afghan Government had announced its desire to assume the “majority of operations in the insecure areas of Afghanistan within three years, and taking responsibility for physical security within five years”, and – as the US was beginning to reduce its troop numbers from the 30,000 deployed during the Bush years – it appeared that the days of a long-term boots-on-the-ground presence by the US military were drawing to a close.

“It’s not an exit strategy, it’s about assisting the Afghans,” insisted then-Secretary of State Hillary Clinton, arguing that the transition from a full US military presence to a more advisory force would coincide with a number of US military personnel staying on – indeed, several thousand – to assist Afghanistan in necessities from developing its counterterrorism networks to building its police force.

A shift in strategy

For the US military, this is a major shift in its mode of operation. Having spent almost 15 years with its troops engaged what is essentially a military occupation, the army is readjusting to a new future in which American interests can be protected abroad without expending the manpower – and significant expenditure – that boots on the ground require. Amid growing budgetary pressure on the Pentagon, the military could be facing a choice of adapting – or losing precious funding opportunities.

Many in the US Army agree with this necessity. In 2015, Lieutenant-General Gustave F Perna, one of the military’s most senior logistics experts, said that a key priority was the transformation of the world’s most powerful military into a leaner, more flexible fighting machine.

“We have new missions all around the world every day – nine of our ten divisions are committed to those missions outside the United States,” he told an Association of the US Army breakfast meeting. “We are increasing our presence and capability in places we didn’t think we were going to be… but we have not deployed forces in an expeditionary manner since 2003… and our logistics skills have atrophied.”

“[We must] develop agile and adaptive leaders who must be ready and modern to ensure the army is globally responsive and regionally engaged.”

Perna wasn’t the only one to voice such concerns. At a Department of Defense Press Briefing last year, General Raymond T Odierno, then Chief of Staff of the US Army, articulated a vision for a military that was more flexible in its ability to protect American interests overseas.

“We must be interoperable with our allies, as well as other services and joint force,” he said. “We must be expeditionary, we must be scalable, and tailorable in order to meet probably simultaneous requirements around the world, across several different continents.”

The army, Odierno argued, was already initiating a long-term plan for how this new, scaled-down force would function: increasing investment in cybersecurity and developing new “readiness models” to deploy troops more efficiently and quickly.

Much of this new strategy has been supported with a number of significant steps forward. Logistics is crucial for expeditionary forces, as is technology that can increase such forces’ agility – from autonomous convoy operations to intelligent power management distribution systems, or even the development of 3D-printing capabilities that can be used the in field – all of which contribute to this thinking.

The France model

But what of the bigger picture? Michael Shurkin of RAND Corporation has long argued that the US Army should look to the French model to deduce how the world’s most powerful military can conduct interventions and expeditionary operations without becoming embroiled in an operational quagmire.

“In recent years, the US Army’s interest in developing and maintaining ready expeditionary forces has coincided with budget pressures that have generated interest in learning to do more with less,” he writes.

Shurkin points to the French military’s 2013 intervention in Mali. Named Operation Serval, the objective was simple: Islamist militants, some of whom were loyal to al-Qaeda in the Islamic Maghreb, were rapidly pushing towards the country’s capital and imposing a brutal form of sharia on civilians in their wake. France – a long-time ally of Mali since the country’s imperial period – saw the need to act, and act quickly.

After an official request for assistance from the Malian Government, French forces were deployed in January. Fighting alongside regional allies, by the end of the month the Islamist forces were defeated and their leadership had fled the country.

“France fielded a relatively small force put together using small, scalable combined-arms, task-organised units as basic building blocks, and conducted a campaign that emphasised speed and manoeuvrability over force protection,” he writes. “The French force, moreover, was for all intents and purposes regionally aligned, and it demonstrated the benefits that could accrue through its apparently effective operations among, and with, local and regional actors.”

[The US Army] has new missions all around the world every day – nine of our ten divisions are committed to those missions outside the United States.

Shurkin identifies a number of factors that contributed to the French success in Mali: the benefits of the regional knowledge of its forces; a broader expeditionary culture in the country’s armed forces that encourages risk-taking; and flexibility in its organising of troops.

“The French Army in Mali operated using small, scalable and task-organised combined-arms forces (SGTIAs), and built them up or folded them into larger, scalable formations (GTIAs),” Shurkin writes. “These formed and re-formed on the fly as operational needs evolved.

“Moreover, the French organised themselves in this matter by doctrine and practice. They train to do this.”

Food for thought

These are all lessons that could, Shurkin argues, be used by the US Army as the transition to an expeditionary force goes ahead. And although there are naturally significant differences in the two cases – the Americans operate on a substantially higher budget, for instance – Shurkin believes that there are nonetheless many potential lessons to be learned, depending on the circumstances, although there is admittedly no one-size-fits-all solution to the US’s ambitions.

“The French way of war represented by Serval might not be optimal, particularly from the point of view of American commanders, who have far greater resources at their disposal,” he writes. “Among other things, those resources enable Americans to minimise risk in a manner that the French cannot.

“The degree to which the US Army could or should emulate the French is, of course, debatable, and the answer might consist of ‘in some ways, in some cases, for some applications’.”

The problem is that the threats facing the US and its allies are currently stronger than ever, with an increasing number of regions drawing the US into long-term commitments that cannot simply be solved with an expeditionary model.

The rise of ISIS in the Middle East,for example, has pulled the US back into that region, and it has proved challenging for the current administration to argue that their policy is not one of full-scale military intervention.

Moreover, with the number of countries hosting an American presence on the rise – 300 personnel were sent to Cameroon recently to assist in the fight against pro-ISIS militants – it is hard to envisage significant scaling-down in the near future.

“You know, when I said, ‘no boots on the ground’, I think the American people understood generally that we’re not going to do an Iraq-style invasion of Iraq or Syria with battalions that are moving across the desert,” President Barack Obama has insisted.

The Trump effect

So when is an expeditionary force not an expeditionary force? The rise of ISIS in Iraq and Syria has seen American troops, a decade after the controversial invasion of Iraq and just three years since the official withdrawal of military personnel, return to Baghdad.

“The problem is that the expeditionary targeting force can easily become a waste of US blood and money,” Anthony H Cordesman, an analyst at the Center for Strategic and International Studies, wrote last year, in comments quoted by the New York Times. “The Obama administration reacts to every new problem with ISIS by making a limited increase in military force that is too little and too late.”

Too often, it seems, the logistical challenges of organising a well-equipped and flexible expeditionary force mean that policy reverts to the old-fashioned modes of operation.

As with all things in Washington, however, the election of Donald J Trump by the American public in November 2016 could mean that the US Army’s ambitions of scaling down and moving away from full-scale interventionism could become radically altered. However, Trump has spoken of pulling away from the US’s international commitments, focusing on rebuilding American infrastructure and obliging allies such as South Korea and Japan to “pay their fair share” – although he has also expressed the need to “bomb ISIS and take their oil”. What Trump’s presidency will mean for Odierno and Shurkin’s vision of a French-style expeditionary force remains to be seen.