At a hearing of the Senate Armed Services Committee on Tuesday, US Defence Secretary Chuck Hagel and Joint Chiefs of Staff Chairman Gen. Martin Dempsey set the stage for a massive and protracted expansion of US military operations in Iraq and Syria.

“This will require a sustained effort over an extended period of time. It is a generational problem,” Dempsey told the committee.

In his opening testimony, Dempsey contradicted President Obama’s pledge last week that there would be no American troops engaged in combat in Iraq or Syria. “To be clear,” he stated, “if we reach the point where I believe our advisers should accompany Iraqi troops on attacks against specific ISIL [Islamic State of Iraq and the Levant] targets, I will recommend that to the president.”

Obama has already authorised the deployment of 1,600 American military personnel in Iraq, including the placement of US troops with Kurdish peshmerga militia and Iraqi army forces fighting ISIL, more commonly known as ISIS (Islamic State of Iraq and Syria). Speaking on behalf of the US military hierarchy, Dempsey made clear that such advisers could not be confined to headquarters, but would be needed to provide “close combat advising” in complex operations such as dislodging ISIS from urban areas like Mosul.

In remarks bordering on insubordination, Dempsey implicitly criticised Obama when he explained that the president had already turned down the recommendation of Central Command chief, General Lloyd Austin, to deploy American troops as spotters to call in air strikes during last month’s offensive to retake the Mosul Dam from ISIS.

Dempsey’s public disagreement points to tensions with the White House and the degree to which the military and intelligence apparatus are calling the shots in the new US-led war in the Middle East. The real purpose of the military intervention, a revival of plans shelved last year, is the ouster of Syrian President Bashar al-Assad. This will necessarily require a far greater American military commitment than currently acknowledged.

In the space of just over a month, what was initially announced as limited air strikes to protect the Yazidi minority in Iraq has been transformed into a full-blown war in Iraq and Syria involving the US and some 40 allies. Both Dempsey and Hagel reaffirmed yesterday that the air war that has already begun in Iraq would be taken into Syria. “This is an Iraq-first strategy… but not an Iraq-only one,” Dempsey said.

Hagel told the Senate Committee that Obama will meet with General Austin today at the Central Command headquarters in Tampa for a briefing on the war preparations. “The plan includes targeted actions against ISIL safe havens in Syria—including its command and control, logistics capabilities, and infrastructure,” he stated.

Hagel dismissed any notion of Syrian national sovereignty, declaring that “our actions will not be restrained by a border in name only. As the president said last week, ‘if you threaten America, you will find no safe haven.’”

As was the case in the 2003 invasion of Iraq, the Obama administration is launching an illegal war of aggression over the vocal opposition of the Syrian government, which is well aware that it is the real target.

While maintaining the pretext of destroying ISIS, Hagel put Assad squarely in the US cross-hairs. “As we pursue this program,” he declared, “the United States will continue to press for a political resolution to the Syrian conflict resulting in the end of the Assad regime. Assad has lost all legitimacy to govern, and has created the conditions that allowed ISIL and other terrorist groups to gain ground and terrorise and slaughter the Syrian population.”

The cynicism is staggering. For the past three years, the Obama administration and its allies, especially Saudi Arabia and the Gulf states, have backed, financed and armed the anti-Assad militias to overthrow the Syrian government. Having turned a blind eye to atrocities carried out in Syria by ISIS and other reactionary Islamist forces, Washington has seized on the beheading of two American journalists to justify the launching of a war to oust Assad.

Along with US air strikes in Syria, Hagel detailed plans to “train, equip and resupply more than 5,000 [Syrian] opposition forces over one year. The package of assistance that we initially provide would consist of small arms, vehicles, and basic equipment like communications, as well as tactical and strategic training.”

Hagel’s claims that there will be “a rigorous vetting process” to ensure that “weapons do not fall into the hand of radical elements of the opposition” have no credibility. The very fact that the training will take place in Saudi Arabia, one of the chief backers of Islamist militias in Syria, including ISIS, makes clear that the “vetting” will be to ensure that the overriding commitment of these forces is to oust Assad.

In his remarks, Dempsey spoke of the need to “destroy ISIL in Iraq,” where it threatens the stability of the US puppet regime in Baghdad. But he set a more modest goal for Syria, where the Islamist organisation could still be called on as part of the regime-change operation against Assad. There he said the aim was to “disrupt ISIL.”

Dempsey also indicated that the US was pressuring unnamed Sunni Arab nations with “very considerable” Special Forces to commit troops to assist anti-Assad militias on the ground in Syria. While he did not name specific countries, they likely include Qatar and Saudi Arabia, whose intelligence agencies have undoubtedly been active inside Syria.

A revealing exchange in the Senate hearing involving Republican Senator John McCain with Hagel and Dempsey underscored the purpose of the unfolding war. After declaring that it was a “fundamental fallacy” to rely on the Syrian opposition to prioritise fighting ISIS ahead of fighting Assad, McCain asked whether these militias would receive American air cover if attacked by the Syrian military.

The question came too close to the truth—that such an attack, real or fabricated, would provide a convenient pretext for unleashing devastating air strikes against the Syrian military. Responding to McCain, Hagel did not rule out the possibility, simply saying: “We’re not there yet, but our focus is on ISIL.”

Dempsey was more open, stating that “if we were to take [fighting] Assad off the table, we’d have a much more difficult time” persuading the Syrian opposition to join the US-led war. He said the administration had an “ISIL-first strategy”—meaning an open assault against Assad would soon follow.

Behind the backs of the American people and without even the fig leaf of congressional authorisation—which both parties would overwhelmingly provide, if asked—the Obama administration is embarking on a reckless and illegal war of aggression aimed at securing US hegemony over the Middle East and beyond. While Assad is the immediate target, the US is preparing for a confrontation with his backers—Iran and Russia—that threatens to trigger a far more devastating war.