Within days of the September 11, 2001 attacks it was clear that the Bush administration would exploit the terrorist attacks to push for war on Afghanistan and Iraq.

What is less well known is the huge transformation that occurred at the heart of the US government in those dark days – the topic of US journalist Jeremy Scahill’s new book Dirty Wars: The World Is A Battlefield. With the nation in a state of collective hysteria, the neoconservatives led by vice-president Dick Cheney and defence secretary Donald Rumsfeld rewrote the rules of the game, instituting a huge expansion of covert US wars.

Scahill (pictured) spoke to me in London earlier this month about how covert action, secret prisons, drone strikes and assassination all began to be deployed on an unprecedented scale.

Having reported from Iraq, Afghanistan, Somalia and Yemen, the 38-year-old national security correspondent for The Nation magazine is one of the most knowledgeable observers of the so-called “war on terror.”

According to Scahill, the Central Intelligence Agency (CIA) was sidelined after the World Trade Centre attacks, with Cheney and Rumsfeld viewing the CIA “as a worthless, liberal think tank.”

Instead they massively increased the funding and power of the elite Joint Special Operations Command (JSOC) – “the most closely guarded secret force in the US national security apparatus,” as Scahill describes it.

Formed in the 1980s and modelled on the British SAS, president Bill Clinton had muzzled the force following its disastrous involvement in the Black Hawk Down episode in Somalia in 1993.

But after the September 11 terror attacks the Bush administration let JSOC “off the leash,” Scahill says.

Or as CIA counter-terrorism centre chief Cofer Black put it: “All you need to know is that there was a before 9/11, and there was an after 9/11. After 9/11 the gloves came off.”

JSOC’s primary role was established during the occupation of Iraq, Scahill says.

“The myth was that ‘the surge’ created this relatively stable couple of years in Iraq” – that US commander General David Petraeus instituted a brilliant counter-insurgency campaign.

However, “everyone in the US military knows this is just a fraudulent portrayal.” Rather “it had everything to do with JSOC creating a kind of Murder, Inc operation where it went down and just killed a tremendous number of people. There was no-one left to kill at one point,” he says bluntly. “JSOC had killed its way through every mom-and-pop resistance operation all the way through to al-Qaida in Mesopotamia.”

This, along with the US paying Sunni tribes, the “awakening councils,” not to kill US soldiers, was what was responsible for the lull in fighting, according to Scahill.

In the run-up to the Iraq war, the public in Britain was often told that one of the reasons Tony Blair was supporting president Bush so closely was that he would be able to influence, and hopefully constrain, US policy.

Scahill laughs when I raise this argument.

“The notion that Blair was going to rein in Bush or Cheney is laughable. If anything Britain was used as a cover by the United States to give legitimacy to the Iraq war.”

In actual fact British forces were “deeply involved” in the assassination campaigns waged by JSOC in Iraq, with British units heading up JSOC operations, he explains.

Scahill is also very critical of President Barack Obama’s record in office – noting how the first black president came under intense pressure from the US military establishment to massively expand the covert wars in Pakistan, Somalia and Yemen.

“And elsewhere – they were asking for authority in the Philippines and Indonesia and certain cases in Latin America, they wanted covert action inside Iran,” he notes.

Enamoured by the generals and admirals, the Obama administration caved in and “start hitting in Pakistan at three or four times the rate Bush was authorising.” Similar upswings in drone strikes, and the inevitable civilian casualties, occurred in Yemen and Somalia.

“Obama was trying to find a way to continue some of these policies by simply tweaking them, or adjusting them in a small way,” Scahill says.

“He ended extraordinary rendition by the CIA and closed CIA black sites. Instead what he is doing is working with human rights-abusing forces around the world to do it for the United States.

“So it’s by proxy now.”

More broadly, Scahill believes “Obama has tried to find a way to legitimise the core of the Bush-Cheney programme while defending the system itself from attack both internally and externally. And it’s been pitched that this is a cleaner, more legal way of waging war.”

Has it worked?

“I think he has largely been effective in selling that idea to liberals.”

Scahill isn’t a pacifist – he believes in the right of the state to defend itself.

But US policy “is just self-defeating.

“My fear is that we are actually creating more new enemies than we are killing terrorists,” he says.

“What’s our security going to look like 10 years from now as a result of killing innocent people in Yemen, Somalia and Pakistan?

“If you and I sit down a decade from now I’m sure we will be talking about attacks that took place as a result of policy implemented right now.”

A key reason so many US citizens either actively support or are ignorant about these damaging actions is arguably the media’s inability to hold the US government to account since the 2001 attacks.

“I don’t believe there is a conspiracy with fat white guys smoking cigars in a back room and deciding how they are going to screw the little people,” Scahill says. “It’s unnecessary.

“Powerful people in government are close friends with powerful people in the media.

“They are part of the same class of people. They hang out together at weekends. They have their little parties like the White House Correspondents’ Dinner where the president jokes about drones and the powerful media barons chuckle at his jokes, and their kids go to the same elite private schools.”

Scahill also argues that in the US “the default position is that power is right, that power is telling the truth, that the powerful are to be trusted.

“I think the opposite should be true – that you should always assume that what they are saying is manipulative,” he counters. “You have to be sceptical as a journalist.”

As Amy Goodman, his former colleague at news programme Democracy Now!, once said: “The role of journalism is to go where the silences are.”

By shining a light on the darkest parts of US foreign policy, Dirty Wars is a brilliant example of this noble aim.

With a senior US defence official recently testifying that the “war on terror” will continue for another 10 to 20 years, muck-raking, investigative journalists like Scahill are needed now more than ever.

Dirty Wars: The World is a Battlefield is published by Serpent’s Tail, priced £15.99. A documentary based on the book will be released later this year. For more information, see www.dirtywars.org.