The Obama administration has begun to consider the conflicts in Syria and Iraq as a single challenge, with an al-Qaeda-inspired insurgency threatening both countries’ governments and the region’s broader stability, according to senior administration officials.

At a National Security Council meeting this week, President Obama and his senior advisers reviewed the consequences of possible airstrikes in Iraq, a bolder push to train Syria’s moderate rebel factions, and various political initiatives to break down the sectarian divisions that have stirred Iraq’s Sunni Muslims against the Shiite-led government of Prime Minister Nouri al-Maliki.

Senior administration officials familiar with the discussions say what is clear to the president and his advisers is that any long-term plan to slow the progress of the Islamic State of Iraq and Syria, as the insurgency is known, will have far-reaching consequences on both sides of the increasingly inconsequential desert border between the two countries.

Although spreading faster in Iraq, the advance of ISIS could also force the administration to reconsider its calculations in Syria, where Obama has taken a cautious approach, declining to arm moderate rebel factions or conduct airstrikes on government airstrips, as some advisers have recommended.

“The key to both Syria and Iraq is going to be a combination of what happens inside the country, working with moderate Syrian opposition, working with an Iraqi government that is inclusive, and us laying down a more effective counterterrorism platform that gets all the countries in the region pulling in the same direction,” Obama said at a news conference Thursday. “Rather than try to play whack-a-mole wherever these terrorist organizations may pop up, what we have to do is to be able to build effective partnerships.”

In thinking through options, administration officials say they are drawing on the history of the U.S. experience in Afghanistan and of its own management in recent years of President Bashar al-Assad in Syria. Both cases hold lessons, some learned the hard way, with bearing on the present crisis.

Administration officials are also weighing a set of strategic and legal complications that in key ways will force U.S. policymakers to plan as if the border between the countries still exists, even though for the insurgency’s purposes it does not.

“Everybody here recognizes that you can’t silo what is happening in Iraq from what is happening in Syria,” said one administration official, who, like others, spoke on the condition of anonymity to discuss the internal thinking. “There’s no doubt the border is melting away. But while we look at the two in tandem, our responses in each place will be very different.”

Maliki has asked the administration to carry out airstrikes against Islamist insurgents in Iraq, an invitation that administration officials say would make intervention legal under international law. Obama has yet to decide if such strikes would be effective inside Iraq and what the consequences would be in Syria.

No such invitation exists in Syria, even though moderate rebel groups fighting Assad would welcome U.S. military support.

The U.S. training program for Syria’s moderate rebel forces, also at odds with ISIS, is taking place in Jordan under CIA supervision. That could expand under legislation pending before Congress, which would authorize the administration to allow the military to take over training, greatly expanding its scope, and potentially locating some of it inside Syria.

Officials have concluded that, like Afghanistan and Pakistan, where a porous border provided Islamist fighters with a refuge from U.S. military pursuit for years, the boundary between Iraq and Syria presents a similar challenge.

President Obama spoke and took questions on the situation in Iraq at the White House on Thursday. He said the U.S. is prepared to send up to 300 military advisers to Iraq but reiterated there would be no U.S. combat troops on the ground. (Associated Press)

U.S. drones have been deployed, in part, to address the problem in Pakistan. But that has raised sovereignty complaints in Pakistan, legal challenges in the United States and human rights concerns over civilians killed in the strikes. Obama is considering drone use now in Iraq.

“Any strategy that looks at questions on one side of a border is only going to be successful in pushing problems to the other side of the border,” said another administration official involved in the discussions. “These are not two different fights.”

With ISIS on the march and U.S.-trained Iraqi forces abandoning posts across the north of Iraq, Republicans have renewed their criticism of Obama’s decisions on both sides of the border. But the circumstances have changed over time as the Arab Spring has unfolded unpredictably across the region.

The rapid military gains of the brutal Islamist insurgency have challenged Obama’s postwar plan for Iraq, which relied primarily on slow but steady political progress that would help bring together the long-competing Sunni, Kurdish and Shiite sects in governing.

The Islamists now control much of Iraq’s ethnically mixed north and Sunni Muslim west, regions that bump up against the Syrian border and have long served as transit routes for guns and fighters to and from both countries. The group has seized the oil-dependent nation’s key refinery and remains, for the moment, on the northern and western edges of Baghdad.

“Our focus now is on how we cauterize what is happening in Iraq, how we encourage political responsibility by the Iraqi government, and what we can do to address the source of the threat, which is in Syria,” said one of the U.S. officials.

Obama withdrew all U.S. forces from Iraq at the end of 2011, drawing sharp criticism from some congressional Republicans, who warned that the country was not yet ready to defend itself. Maliki had refused to grant U.S. forces immunity from Iraqi prosecution — a basic element of any troop basing agreement — beyond that year.

Former administration officials say the intelligence assessment regarding Iraq at the time of the U.S. withdrawal predicted that the country would remain secure and stable, although with two important caveats.

The first was that Iraq’s stability could be severely threatened by an “external shock” to the region, as one former administration official involved in the decision put it. Syria’s civil war exploded the following year, creating a refugee crisis of historic proportions.

The second involved Maliki and his willingness, after decades of persecution under the Sunni-dominated dictatorship of Saddam Hussein, to open up the senior ranks of the government and of the military to other sects, namely Sunnis. The administration backed Maliki over Ayad Allawi, a secular Shiite who drew Arab and Kurdish votes, following the 2010 elections in part with the understanding he would do so.

American intelligence officials at the time of the withdrawal also warned that any indications of revolt from the Sunni tribes in Iraq’s western Anbar province, which borders Syria, should be understood as a significant warning sign and threat to the country’s stability.

Those tribes worked with U.S. intelligence agencies and the military in the war’s later phases to roll back Sunni insurgents, including those aligned with ISIS. Antigovernment demonstrations in Anbar flourished last year.

“The intelligence community was both right and wrong — or wrong for the right reasons,” said Colin Kahl, a Georgetown University professor who was responsible for Iraq policy at the Pentagon at the time. “They were wrong to say there would only likely be an uptick in violence, but they were right in identifying the two reasons Iraq could be severely threatened. And both of those things happened.”

Kahl said Maliki resisted proposals for any U.S. forces to remain, including options that called for more than 10,000 troops and would have maintained a presence along the sectarian fault line dividing the autonomous Kurdish province from the rest of northern Iraq.

U.S. troops stood with Kurdish and Arab soldiers along the line for years. That region has emerged again as a Sunni militant hotbed, and a grave threat to Maliki’s government, in the current conflict.

“It was a very visible presence of Americans, that is, Americans serving as peacekeepers between Arabs and Kurds,” Kahl said. “Partly Maliki believed it would give him more leverage with the Kurds if we left, and partly because he didn’t want Americans policing Iraqi ethnic boundaries.”

Administration officials say their planning with both Iraq and Syria is taking into account Assad and Maliki, a pair of problematic leaders with different degrees of political legitimacy.

Maliki won more votes in the recent election than he did four years ago, and the administration, uneasily, is supporting his rule. In Syria, though, Obama called nearly three years ago for Assad to step down, saying he had lost his legitimacy to govern the country. More than 140,000 Syrians have been killed since then.

Administration officials say that, even though internal concerns are growing that Maliki will be able to lead the country through this crisis, there is a reluctance to withdraw backing for the prime minister given his public support and lack of any other obvious alternatives.

As one official put it: “We don’t want to call for Maliki to step down, then spend years trying to figure out how to get him to.”