After more than a decade of war in Iraq and Afghanistan, America’s most profound legacy could be that it set the world order back to the Middle Ages.

While this is a slight exaggeration, a recent examination by Sean McFate, a former Army paratrooper who later served in Africa working for Dyncorp International and is now an associate professor at the National Defense University, suggests that the Pentagon’s dependence on contractors to help wage its wars has unleashed a new era of warfare in which a multitude of freshly founded private military companies are meeting the demand of an exploding global market for conflict.

“Now that the United States has opened the Pandora’s Box of mercenarianism,” McFate writes in The Modern Mercenary: Private Armies and What they Mean for World Order, “private warriors of all stripes are coming out of the shadows to engage in for-profit warfare.”

It is a menacing thought. McFate said this coincides with what he and others have called a current shift from global dominance by nation-state power to a “polycentric” environment in which state authority competes with transnational corporations, global governing bodies, non-governmental organizations (NGO’s), regional and ethnic interests, and terror organizations in the chess game of international relations. New access to professional private arms, McFate further argues, has cut into the traditional states’ monopoly on force, and hastened the dawn of this new era.

McFate calls it neomedievalism, the “non-state-centric and multipolar world order characterized by overlapping authorities and allegiances.” States will not disappear, “but they will matter less than they did a century ago.” He compares this coming environment to the order that prevailed in Europe before the domination of nation-states with their requisite standing armies.

In this period, before the Peace of Westphalia of 1648 ended decades of war and established for the first time territorially defined sovereign states, political authority in Europe was split among competing power brokers that rendered the monarchs equal players, if not weaker ones. The Holy Roman Emperor, the papacy, bishoprics, city-states, dukedoms, principalities, chivalric orders–all fought for their piece with hired free companies, or mercenary enterprises of knights-turned profiteers.

As progenitors of today’s private military companies (PMCs), free companies were “organized as legal corporations, selling their services to the highest or most powerful bidder for profit,” McFate writes. Their ranks “swelled with men from every corner of Europe” and beyond, going where the fighting was until it wasn’t clear whether these private armies were simply meeting the demand or creating it.

In an interview with TAC, McFate said the parallels between that period in history and today’s global proliferation of PMCs cannot be ignored. He traces their modern origins to the post-Cold War embrace of privatization in both Washington and London, both pioneers in military outsourcing, which began in earnest in the 1980s.

By the time the U.S. decided to invade Iraq and stay there in 2003, its smaller peacetime military force structure could not withstand the burden. The Pentagon increasingly relied on contractors to support and wage the war.

“Policy makers, when they started the war in Iraq, they didn’t think it would last beyond a few weeks. They had three terrible choices – they could withdraw prematurely, they could institute a Vietnam-era draft … or they could contract out. So they chose to contract it out,” McFate said. “That is why you have it now and why it is not regulated.”

The U.S. used contractors in Iraq and Afghanistan more than it had in any war in its history: in 2010 there were more contractors deployed to war zones (207,000) than U.S. servicemembers (175,000). In World War II, contractors only made up 10 percent of the military workforce, according to McFate.

From 1999 to 2008, at the peak of the wars, Pentagon spending on outsourcing alone increased from $165 billion to $466 billion a year. Attempts at oversight have been pathetic, as documented by the government’s own inspectors general time and again. Success at regulating or imposing codes of conduct on contractors has proven elusive, too. The industry remains as opaque as it has been unassailable where it really counts—the pocketbook.

“The industry is here to stay; it’s not going anywhere,” said McFate a former employee of Dyncorp, which cut its teeth in Bosnia. Dyncorp thrived as one of Washington’s primary contractors for both security and reconstruction in Afghanistan and Iraq despite intermittent accusations of overbilling and underperformance on the job.

Perhaps the most infamous of all contractors was Blackwater, which deflected charges of fraud, violence against civilians and murder for years before it was forced to “rebrand.” Four of its former guards were convicted of murder in October, however, in connection with the massacre of 17 Iraqis in Nisour Square in 2007.

Blackwater’s founder Erik Prince has dipped and dodged his way through several incarnations of his company (no longer “Blackwater,” it was renamed “Xe” and is now “Academi”), and has been successful at running a number of other so-called shell companies and international security operations inside and outside of the U.S. government trough, including anti-piracy enterprises in North Africa.

In his post-American days (Prince left the U.S. for Abu Dhabi in 2010 amid a series of federal charges and lawsuits dogging Blackwater), Prince perched himself “at the top of the management chain” at Saracen International, a security group made up of hard-core mercenary veterans hired in 2009 to train indigenous forces in Puntland, Somalia, and to serve as a security detail for the embattled president of the fragile central government in Mogadishu.

Saracen was officially kicked out of Somalia in 2011 after accusations were made that it was violating the country’s arms embargo. According to Jeremy Scahill’s seminal “Dirty Wars”, however, by 2013 it was not clear that Saracen had ever left, and it was likely still operating in Somalia at the time with a handful of other international PMCs, including Dyncorp.

This is the world that Prince has both made and has thrived in. According to McFate, “‘irregular’ warfare is more regular than the ‘regular’ warfare,” as the number of internal conflicts have tripled while interstate wars have dwindled in number since a peak in 1965. As a result, PMCs have been used increasingly over the last 15 years by countries, NGOs, and corporations alike to protect ships on the high seas and oil fields in the deserts, to secure humanitarian missions, to raise armies against insurgencies, and to serve as security details at embassies, military bases, and palaces across the Middle East and beyond.

On the darker side, many of the multinationals once on the U.S. dole as PMCs in places like Iraq have since started their own enterprises and taken their skills to clients no matter the mission. They are hard to track, and impossible to rein in.

For example, before Libyan dictator Muammar Gadhafi was killed, he hired mercenaries from across Africa, “to brutally suppress the popular revolt against him,” McFate points out. Likewise, papers reported in 2011 that one of Prince’s companies, Reflex Responses, was hired to raise a force of several hundred guards for the emir of Abu Dhabi, to “assist the UAE government with intelligence gathering, security, counterterrorism and suppression of any revolts.”

By no means has the U.S. stopped using PMCs—they are protecting diplomats in Afghanistan and Iraq, training foreign militaries, and conducting intelligence. At this point they are more agile and better equipped to do this work overseas than even their military paymasters, McFate argues, and their use prevents the public angst—and scrutiny—that accompanies putting American soldiers into harms way.

“The argument about private militaries being here to stay – that is the truth or unfortunate truth depending on your position,” said Peter Singer, senior fellow for the Future War project at the New America Foundation and author of Corporate Warriors: The Rise of the Privatized Military Industry.

“For those who thought this would all be over with the end of Iraq 2.0 or Obama’s presidential victory, the facts just don’t bear that out,” he told TAC in an interview. Singer agrees with McFate’s assessments in Modern Mercenary, which he said

“mixes the analytic and academic side with his own personal experiences working for one of the firms; that combination is rare in this space.”

McFate details for the first time in public how he was hired by Dyncorp on behalf of a secret U.S. contract to help prevent a group of Hutu rebels, the Forces Nationales de Liberation (FNL), from sparking another genocide of the Tutsis during the ongoing civil war in Burundi. McFate was tasked at one point with guarding the president of Burundi from impending assassination. The president remained safe, and the civil war was brought to an end by 2005.

McFate said he wrote about this, and Dyncorp’s training of the Liberian army in 2011, to show in part that PMCs can be used to positive ends. But he is not naïve. He is clear about where they can fail, invite mission creep, or seize power for clients through violence. By their very nature, PMCs profit from conflict and are always at risk of creating and expanding it for their own benefit. McFate cites numerous examples throughout history in which mercenaries have played both sides, only to come out with full pockets.

In addition, private armies live by no rules of war or international conventions; here, Erik Prince is the best example. PMCs can hide in countries with the lowest standards and norms. They have access to a global arms trade and the latest military technology, including drones. They are a risk to civilian populations, and their operations are never transparent. “You can FOIA (Freedom of Information Act) the CIA, you can’t FOIA this industry,” said McFate.

So what to do? McFate suggests that banning PMCs or trying to regulate them into submission won’t work because it would only drive them underground and into the realm of rogues. He suggests letting the market work to “incentivize desirable practices by making them profitable” might be the best course. He notes, however, that when the U.S. military had “market power” and was in the best position to set price and practices at the beginning of its wars, it “failed to do so.”

Whether the cons of private contracting outweigh the pros is a debate McFate chooses not engage, and his background as both soldier and contractor figure heavily in the tenor of his book. “I leave it deliberately up to the reader,” he said. “The book is not an argument; it’s more about exploration. There is a big global trend happening right under our feet. I think we are in the precipice of a big decision.” That decision is how to deal with the privatization of war effectively, if at all.

It will not be easy. U.S. agencies knowingly hired companies with spotty records. They used private contractors for controversial secret operations, including the detainee interrogations at Abu Ghraib, and a covert CIA assassination program involving Blackwater. It will take a lot more trust in Washington to believe that “best practices” in this industry can genuinely come from government itself.

“In an idealized world the companies with the best practices and best performance records would end up with all the contracts, and the bad actors would be eliminated from the field,” said Singer. “That hasn’t happened in regular business, much less when you cross regular business with what you call politics.”

Or war. Get your seat belt on, because if McFate is right, it is “back to the future,” and any choice we might have had in the matter is long gone.

Kelley Beaucar Vlahos is a Washington, D.C.-based freelance reporter and TAC contributing editor. Follow her on Twitter.