Twenty years after the start of the Iraq War, one question remains difficult to answer convincingly. Just why did the United States, under President George W Bush, invade and occupy Iraq? Answers from academics and think tanks range from the need to safeguard oil supplies held by a rogue state that had taken over Kuwait and now controlled a fifth of the world’s oil reserves, through to Iraq supporting terrorism and developing weapons of mass destruction.

Such answers may be plausible enough and include a degree of truth, but we still have to ask: why go to war then? It was barely a year since the US and a few partners had terminated the Taliban regime in Afghanistan. The US had defeated and dispersed the al-Qaeda movement behind the 9/11 attacks, so if the so-called ‘war on terror’ was over, why take on Iraq?

The US domestic political context is important here. Democrat president Bill Clinton had served two terms from 1993 to 2001, and over that time a hard-right vision had emerged within the Republican Party.

Those within this prominent faction – known as neoconservatives – were utterly convinced that Clinton had been a disaster. As they saw it, the collapse of the Soviet Union at the start of the 1990s had given the US a God-given opportunity to play a unique and timely leadership role in the development of a global system rooted in neoliberalism, supported by US military power.

The highly influential foreign policy lobby group Project for a New American Century was founded in 1997 from a conviction that the United States should play a near-messianic role, in marked contrast to the weak self-serving Clinton administration. And months after George W Bush’s inauguration and shortly before 9/11, leading neoconservative writer Charles Krauthammer claimed the US had the right to pursue unilateral policies in the wider global interest:

Multipolarity, yes, when there is no alternative. But not when there is. Not when we have the unique imbalance of power that we enjoy today – and that has given the international system a stability and essential tranquillity it had not known for at least a century.The international environment is far more likely to enjoy peace under a single hegemon. Moreover, we are not just any hegemon. We run a uniquely benign imperium.

(...) Indeed, the biggest surprise in these Iraqi elections has been that Moqtada al-Sadr's latest political re-invention was successful. The Shia leader did not always wear the robes of a nationalist political leader seeking an alliance with secular forces.

After the invasion of Iraq in 2003, al-Sadr's only political asset was the reputation of his father, Ayatollah Mohammed Sadiq al-Sadr, a prominent Shia cleric who opposed Saddam Hussein and who was a rival of top Shia cleric Ayatollah Ali al-Sistani.

Moqtada al-Sadr inherited a network that his father - who was assassinated in 1999 by Iraqi intelligence agents - had developed among Iraq's urban poor and disenfranchised who endured hardship during the Baathist regime. In 2004 he put together a militia called Jaish al-Mahdi (the Mahdi Army), which attacked US occupation forces. Four years later, he announced the disarming of his militia and attempted to disavow the use of violence.

Sadr then reinvented himself as a grassroots Shia and Iraqi nationalist leader, who stood above the fray of partisan Shia politics in parliament and embraced the politics of protest. In 2016, he formed an alliance with the ICP and other secular groups that had been instrumental in organising anti-corruption rallies for the past three years.

They demanded that the government reform the political system, clamp down on corrupt officials and ensure judicial independence. In 2016, al-Abadi conceded to these demands and put forward a list of technocrats who were meant to replace ministers affiliated with various political forces. He failed to pass this motion in a recalcitrant parliament after parties who rely on these ministerial positions for patronage and distribution of funds blocked it.

In June 2017 the Sadrists and the communists agreed to run in the 2018 elections together. Despite their differences, the parties ran on a platform appealing to marginalised groups and combating social inequality. The alliance was meant to demonstrate to the public al-Sadr's formal renouncement of sectarian politics and adoption of nationalist rhetoric. (...)

(...) Shortly afterward, Bush himself mentioned Kamel, as did Colin Powell in his address to the U.N. Security Council.

This so infuriated someone with access to the detailed notes from one of Kamel’s original debriefings that he or she leaked them to Newsweek, which finally published a brief story about Kamel on March 3, 2003, just a few weeks before the war began. Newsweek did not mention Cheney’s lie about Kamel, but did explain that “the defector’s tale raises questions about whether the WMD stockpiles attributed to Iraq still exist.”

When subsequently questioned by Reuters for a follow-up story, the CIA and MI6 were clearly terrified and went ballistic. The British hilariously claimed that “We’ve checked back and he didn’t say this. He said just the opposite, that the WMD program was alive and kicking.” According to the CIA’s then-spokesperson Bill Harlow, the Newsweek story was “incorrect, bogus, wrong, untrue.” (Harlow, who now makes a living defending the CIA’s torture program, recently told me that “I have no intention to engage in an exchange about that single answer to one of the thousands of questions I handled in that job more than a decade ago.”)

The CIA’s fear was understandable. At just about the same time, Alan Foley, the head of the CIA division in charge of analyzing Iraq’s purported WMD programs, was — according to retired CIA analyst Mel Goodman — privately saying that Iraq possessed “not much, if anything” related to WMD.

The rest of the story is well-known: The U.S. and allies invaded Iraq on March 19, 2003, and Iraq had become a perpetual vortex of violence that may pull in the entire Mideast. We now know not just what Kamel had said in 1995, but that he’d been telling the truth.

Thus even if you disregard the mountains of evidence that the Bush administration shaded the truth, omitted pertinent facts, and straight-out lied in other areas, the story of Hussein Kamel tells you everything you need to know. Indeed, the Bush administration’s campaign of deceit was so successful at so little real cost that it continued with even more brazen post-invasion lies. For instance, Bush went on to claim that Saddam Hussein “absolutely” had WMD programs and repeatedly said that Iraq “wouldn’t let (U.N. inspectors) in.”

So hopefully Trump won’t buckle to the pressure from the Republican establishment to proclaim that the Bush administration’s WMD claims were all just an honest mistake. They weren’t, and Trump was absolutely right.

Barack Obama authorised “up to 450 additional military personnel” to be deployed to the eastern Anbar province, the White House announced on Wednesday. The reinforcements will bring the number of US military forces in Iraq to 3,550.