SALT PIT, CIA PRISON, KABUL, AFGHANISTAN - SEPTEMBER 1, 2014 -- DigitalGlobe satellite imagery of a the Salt Pit outside of Kabul, Afghanistan. The Salt Pit was the codename of an isolated clandestine CIA black site prison and interrogation center in Afghanistan. It is located north of Kabul and was a brick factory prior to the Afghanistan War. The CIA adapted it for extrajudicial detention. (Photo DigitalGlobe via Getty Images)

One big revelation in the explosive summary of the Senate report on CIA torture is just how much the U.S. government is outsourcing its dirty work.

The 500-page report on CIA interrogation tactics, released last week, details shocking instances of waterboarding, forced rectal feedings and various other torture methods, in one case leading up to a detainee's death. It also includes a somewhat-overlooked statistic: Eighty-five percent of the interrogations completed as part of the CIA's covert program in the wake of 9/11 were conducted by private contractors, who were paid tens of millions of dollars for actions.

The use of contractors for interrogations continues a recent, troubling trend of the U.S. government giving some of its hardest jobs to companies motivated by profit. It raises moral and logistical questions about the use of such contractors, several experts told The Huffington Post, and could make it more difficult to hold people accountable for any crimes committed in the course of the CIA interrogation program.

“These people are outside the normal rules of the game,” said Brigitte Nacos, an adjunct professor of political science at Columbia University who specializes in counterterrorism. Nacos noted that contractors like the psychologists who the report describes as the main architects of the CIA interrogation program are not subject to court martial. “I think in this case it was a big mistake,” she said.

Fighting wars with outside help isn’t new. As far back as the American Revolution, contract personnel have played an important role in armed conflicts. But the use of contractors to fight the nation’s wars has increased in recent decades. And in the future, those who study this issue say, contractors will continue to prove useful in maintaining America's role as global policeman.

On average, there was just one civilian contractor in Vietnam for every six active duty soldiers fighting there, according to the Office of the Under Secretary of Defense for Acquisition, Technology and Logistics, which establishes policies for Defense Department contracts. In the Iraq War, that ratio rose to 1 to 1. During the U.S. occupation of Iraq, there were at least 200 different private security companies in operation, according to a 2009 report from the Peace Research Institute Oslo, a think tank.

The government employs for-profit companies to supplement the work done by regular soldiers because there’s a belief that it’s cheaper, and because it’s an easier sell to voters who are often reluctant to send troops overseas. Contractors can also be appealing because they let government agencies bring in outside expertise and avoid a lot of the red tape that can be a drag on efficiency.

That may have been the thinking behind hiring the two psychologists whose consulting company was given an instrumental role in conducting the CIA’s interrogations of detainees at “black sites” overseas, said Gregg Bloche, a professor at Georgetown Law School. Bloche wrote extensively about the two psychologists in his book, The Hippocratic Myth.

The Senate report describes how the pair, who had previously trained members of the military as part of a U.S. Air Force program called the Survival Evasion Resistance And Escape Program (SERE) on how to resist torture in case they were captured in enemy territory, proposed various torture methods and oversaw interrogations.

“Making them [the psychologists] into contractors let them shape and manage the CIA program with much less bureaucratic restrictions,” Bloche said.

But contractors are also harder to supervise than salaried government employees, according to Bloche and others who study privatization. Because military and intelligence contractors work outside government agencies’ chains of command, the contractors can be less accountable when things go wrong. Private companies don’t always have the same disciplinary mechanisms and clear-cut lines of authority as government agencies like the Department of Defense and the CIA.

“There’s more ability to directly supervise someone if they’re a [government] employee or on active duty than if they’re a contractor,” Bloche said. In this case, he added, it might not have mattered -- Bloche said he believes the CIA had no desire to supervise interrogators anyway.

In a 120-page response to the Senate report, which was written in June 2013 but declassified this month, the CIA said that the two psychologists who devised and carried out the interrogations “had the closest proximate expertise available to CIA at the time the program was authorized.” The agency's response cited the psychologists’ time working for the SERE program as an example of their relevant experience. The CIA declined to comment for this article.

Although torture is a violation of both international and federal law, and Obama banned the use of harsh interrogation techniques in 2009, the two psychologists almost certainly won’t be prosecuted. The same is true of their employees, many of whom were private contractors and directly participated in the controversial interrogations, according to the Senate report. Obama has said he wants to leave the incidents “where they belong -- in the past,” and the Justice Department has explicitly said it will not prosecute the torturers.

While the contractors could be prosecuted by the International Criminal Court, it’s extremely unlikely that will happen, said Eric Stover, a law professor and the faculty director of the Human Rights Center at the University of California, Berkeley. If it decides to take action at all, the court is more likely to go after the high-level officials who authorized the torture, rather than the contractors who carried it out. “They usually go after those most responsible for the most serious crimes,” Stover said.

If they were to be prosecuted, taxpayers would end up footing the bill. The CIA has agreed to pay the legal expenses for the psychologists' company through 2021, the Senate report said.

Historically, contract interrogators are almost never put on trial for crimes. There’s only one case in U.S. history where a private contractor has been convicted of abusing detainees -- David Passaro, a CIA contractor sentenced to eight years in prison for beating an Afghan detainee, Abdul Wali, with a flashlight in 2003. (Wali died the day after the beating.)

Passaro may have thought that as a contractor, he wasn’t bound by regulations that apply to active duty military members. According to testimony from Assistant U.S. Attorney Pat Sullivan during Passaro's trial, the contractor told soldiers that they weren't allowed to touch Wali but he could, "because I have special rules."

The problem is that government agencies sometimes draft their contracts sloppily, with little attention to important issues such as the training and vetting of employees, said Laura Dickinson, a professor at George Washington University Law School who studies human rights, national security and foreign affairs privatization.

Then, if contractors commit abuses, “we don’t have a viable accountability system to ensure that they’re held accountable,” she said.

There is a federal law that exists specifically for prosecuting military contractors who break the law in foreign countries. But Dickinson said that law -- the Military Extraterritorial Jurisdiction Act -- is ambiguous about contractors who work for agencies besides the Department of Defense. (CIA contractors, for example, might not be subject to the law as it is currently written.)

There have been some convictions of contractors, including the Passaro case and Blackwater Worldwide. Blackwater was the private security firm accused of fatally shooting 17 people at a Baghdad intersection in 2007. In October, four of the firm’s guards were sentenced to prison for the incident. Lawyers for the jailed contractors have vowed to appeal the decisions.

On the other hand, no private contractors were convicted of any crimes in connection with the abuse of prisoners at Abu Ghraib, the Iraqi prison that U.S. forces used after the 2003 invasion to detain terror suspects.

A bill to hold contractors from all government agencies accountable for breaking laws overseas -- dubbed The Civilian Extraterritorial Jurisdiction Act -- was introduced in Congress in July. Although the bill would close the loophole left open by existing law, Dickinson noted that it has languished on Capitol Hill for years and stands little chance of being passed soon.

“We still lack a comprehensive legal framework for ensuring that contractors who commit abuses are held accountable,” she said.

The use of contractors has been curbed somewhat in recent years. In 2009, the CIA banned the practice of hiring contractors to question detainees, and the Department of Defense followed suit in 2010. But the Defense Department’s new rules make an exception for cases “vital to national security.”

The expanded fight against the Islamic State in Syria and Iraq may mean more private contractors being used to carry out government work in foreign countries. The Department of Defense sent surveys to contractor firms in July and August of this year to gauge their interest in doing work in Iraq like providing security assistance to the Iraq Ministry of Defense, Dickinson said.

“Obama said there’d be no boots on the ground [in Iraq or in Syria], so the incentive to use contractors is high,” Dickinson said.

As long as the public remains reluctant to send American soldiers to overseas wars, the government is likely to continue to hire private-sector companies to perform important security work around the world.