After overrunning Mosul, Iraq’s second-largest city with a population of roughly 2 million, the Islamic State of Iraq and the Levant (ISIS), a Sunni militia that is an offshoot of Al Qaeda, has continued its offensive, taking Tikrit, the hometown of former Iraqi leader Saddam Hussein, and a number of other towns in the Tigris River valley on the road to Baghdad.

The government of Prime Minister Nouri al-Maliki has thrown Iraqi special forces units along with volunteers raised from the Shia population into a defensive line north of the capital in hopes of breaking the ISIS advance.

The US is reportedly beginning to evacuate some of the thousands of military and intelligence contractors deployed in the country, and there are discussions over what will be the fate of the giant US embassy in Baghdad, the largest in the world. What is unfolding is a monumental debacle engendered by the entire policy pursued by both the Bush and the Obama administrations over the course of more than a decade.

The crisis threatens to plunge Iraq into a sectarian civil war on the scale of the one provoked by the US and its allies in neighboring Syria and to engulf the entire region in bloody conflict.

Washington, which just two and a half years ago ended nearly a decade of occupation and war that claimed some one million Iraqi lives, is inevitably being drawn back into a catastrophe of its own making.

“I don’t rule out anything,” President Barack Obama said Thursday in response to White House reporters’ question about a potential US military response to the ISIS offensive.

Describing the crisis in Iraq as an “emergency situation,” the US president said that it was clear that the Iraqi regime of President Nouri Maliki is “going to need more help.”

A White House spokesman hastened to clarify afterwards that Obama was not referring to the return of US troops to Iraq, a country occupied by the US military for nearly nine years until the end of 2011, but rather only to potential US air bombardments and drone missile strikes.

Washington has also pledged to rush shipments of Hellfire missiles along with millions of rounds of small arms ammunition, thousands of tank rounds, grenades, machine guns and assault rifles to the Iraqi military.

These armaments, however, are not likely to arrive in Iraq within the next few weeks, and the Iraq army that they are supposed to assist is in a state of disintegration. In Mosul and elsewhere, Iraqi soldiers have deserted en masse, laying down their weapons, discarding their uniforms, changing into civilian clothes and attempting to flee the Islamist guerrillas.

A force that the US military spent $25 billion and nearly a decade to train has proven incapable of halting the advance of what are estimated to be only 2,000 to 3,000 ISIS fighters. Videos posted online showed ISIS fighters herding columns of hundreds if not thousands of soldiers taken prisoner.

The Maliki regime, which was installed under the US occupation, is in terminal crisis. The prime minister, who also holds the titles of commander-in-chief of the military, defense minister and interior minister, has been unable to form a government since elections held in April. On Thursday, he attempted to convene a parliamentary session to pass legislation imposing a nationwide state of emergency. No vote could be held, however, as the number of legislators assembled fell far short of a quorum, with Sunni, Kurdish and rival Shia parties boycotting the session out of opposition to the already autocratic and sectarian methods employed by Maliki.

The scope of the ISIS victory and of the debacle for the United States and the regime that it installed became clearer Thursday with the Islamists staging a parade in Mosul of US-supplied Humvees and other armored vehicles, accompanied by an overflight of captured military helicopters.

Their ability to deploy these aircraft pointed to the growing involvement in the insurgency of former officers and soldiers of the old Iraqi army, which was disbanded under the US occupation regime. Reportedly among them is Izzat Ibrahim al-Douri, the former Iraqi general and vice president, who became the head of the banned Baathist Party following the execution of Saddam Hussein. In some of the towns they have overrun, the ISIS has reportedly set up military councils headed by ex-Baathist officers to serve as the local government.

There have also been scenes of crowds celebrating the routing of the Iraqi army, which has long been viewed in predominantly Sunni areas in the west and north of the country as an occupying force of a hostile Shia regime

These bitter sectarian divisions were greatly exacerbated by the US war of aggression launched in 2003 and the subsequent divide-and-conquer strategy of the American occupation. They have been deepened by the Maliki regime, which has systematically worked to exclude the Sunni population from power and treated all political opposition in Sunni areas as “terrorism,” sending in the military to suppress peaceful protests. In the present crisis, Maliki has appealed directly to Shiite sectarianism, describing the struggle against ISIS as a “holy war.”

There are mounting indications that the crisis triggered by the ISIS offensive could lead to the complete fracturing of Iraq along sectarian lines and draw in other regional powers as the chaos created by the series of US imperialist interventions threatens to shatter the existing political map of the Middle East.

The Kurdish military force, the peshmerga, has taken control of all of the city of Kirkuk in northeastern Iraq after the Iraqi military melted away there too. The city, which is a key center of Iraq’s oil industry, is divided between Arabs, Kurds and Turkmen, but the Kurdish movement has always claimed it as its capital. US occupation authorities forced the peshmerga to relinquish control of Kirkuk after they took it during the 2003 invasion and afterwards opposed any joining of the city to the nearby autonomous Kurdish region.

Kurdish politicians in Erbil have greeted the collapse of the Iraqi army as a “golden opportunity” to incorporate the strategic oil capital into Iraqi Kurdistan. The Iraqi central government will oppose the Kurdish takeover of the city, as will the other ethnic populations and most other states in the region.

Between the advances of the ISIS and those of the Kurdish peshmerga, the regime in Baghdad could be left ruling little more than the capital and the Shia heartland in the south.

Meanwhile, both Turkey and Iran have threatened to intervene in Iraq. Turkish officials warned of retaliation over the ISIS capture of 49 people at the Turkish consulate and Mosul as well as their seizing 31 Turkish truck drivers as hostages.

“Any harm to our citizens and staff would be met with the harshest retaliation,” warned the Turkish foreign minister, Ahmet Davutoglu, Thursday in New York City after canceling meetings at the United Nations in order to fly back to Ankara to deal with the crisis.

In Tehran, President Hassan Rouhani, declared Thursday that: “Iran won’t stand still, and we aren’t going to tolerate those terrorists. We’re going to intervene at the appropriate time to combat terrorism in the region and around the world. As I said before in front of the UN, this terror wave embraces a clear message to us as Muslims that our enemies will do whatever possible to incite sectarian and ethnic strife among us.”

According to unconfirmed reports, Iran has already sent a unit of the Revolutionary Guards Quds Force into Iraq to assist in the struggle against ISIS and has beefed up military forces on the Iraqi border.

Whether Washington will directly intervene in Iraq is still unclear. The Maliki regime has reportedly renewed calls it has been making since the Iraqi prime minister’s visit to Washington last November for the US to carry out air strikes against the Islamist militias and Sunni insurgents.

The reaction of official Washington to a debacle on the scale of Saigon’s fall nearly four decades ago has been decidedly muted. Obama’s remarks were delivered in a brief appearance alongside Australian Prime Minister Tony Abbott. And, while the Republican Speaker of the House John Boehner made a jibe Thursday about Obama “taking a nap” during the Iraq crisis, he made no calls for any specific response to the ISIS offensive.

In large measure, this reaction can be explained by the glaring lies and contradictions that pervade US imperialism’s criminal and reckless interventions in the Middle East. While claiming to support Maliki against Islamist militias in Iraq, Washington is backing these same forces as a proxy army in a bloody sectarian war for regime change in Syria. Officially, the Obama administration has branded ISIS as a terrorist organization, but in reality it constitutes one of the main fighting forces in the war to topple President Bashar al-Assad.

The overrunning of Mosul has objectively served a stated goal of US policy, which is to strengthen the forces fighting the Syrian government. The largest share of the war booty captured in Mosul, including hundreds of armored vehicles, huge quantities of arms and ammunition and hundreds of thousands of dollars in cash, has been sent back across the effectively erased border to Syria.

The net effect of Washington’s policies—waging a war of aggression in Iraq on the phony pretext of battling “terrorism,” and backing Al Qaeda-linked militias in a proxy war in Syria—has been the death, maiming or displacement of millions of innocent people on both sides of the border.