Last Updated Sep 4, 2014 4:29 PM EDT
NEWPORT, Wales -- NATO leaders grappled Thursday with whether the alliance has a role in containing a mounting militant threat in the Middle East, as heads of state converged in Wales for a high-stakes summit also focused on the crisis in Ukraine and next steps in Afghanistan.
President Obama and British Prime Minister David Cameron declared that their nations would "not be cowed" by extremists from the Islamic State of Iraq and Syria, or ISIS, who have claimed responsibility for killing two American journalists. They also challenged NATO to not turn inward in the face of the threat.
"Those who want to adopt an isolationist approach misunderstand the nature of security in the 21st century," Mr. Obama and Cameron wrote in a joint editorial in the Times of London. "Developments in other parts of the world, particularly in Iraq and Syria, threaten our security at home."
Mr. Obama, Cameron and dozens of other NATO leaders met on a golf resort in Wales for the two-day summit. Leaders here also planned to commit to a more robust rapid response force on its eastern flank, which would aim to serve as a deterrent to Russian aggression.
Yet much of the action was to take place on the sidelines of the summit, where the American and British leaders were expected to drum up support for an international response to confronting the militants of ISIS, also known as the Islamic State of Iraq and the Levant, or ISIL, in Iraq and Syria.
Arriving at the summit site on Thursday, NATO Secretary-General Anders Fogh Rasmussen said he believes the broader international community "has an obligation to stop the Islamic State from advancing further," but noted that the alliance hasn't received any request for help.
"I'm sure that if the Iraqi government were to forward a request for NATO assistance, that would be considered seriously by NATO allies," Rasmussen said.
Mr. Obama also met Thursday with Jordan's King Abdullah II, a key U.S. ally in the Middle East that's caught in the crossfire of the region's instability.
ISIS militants have claimed responsibility for murdering two American journalists, releasing gruesome videos of their beheadings. Both the U.S. and Britain are deeply concerned about the potential threat to their homelands that could come from the foreign fighters who have joined the violent ISIS group.
Mr. Obama has come under pressure at home to iterate a clear strategy to counter ISIS, whose militants have faced American airstrikes in Iraq. The group's leadership is believed to be located across the border in Syria, and Mr. Obama conceded last week that to date, his administration had no clear policy on how to counter the terrorists.
"The president is clearly grappling with not just what our strategy is but what our overall commitment will be to engaging this group," said CBS News national security analyst Juan Zarate. "If he commits fully to the destruction of this group, in many ways that would be a declaration of war yet again in the heart of the Middle East, something that this president's administration might find politically unpalatable and difficult to defend."
Former CIA deputy director Mike Morell says finding a way to counter ISIS inside Syria must be a part of any strategy the U.S. pursues against the group, but any action taken by Mr. Obama inside Syria comes with the added complication of at least appearing to help another foe of the United States.
"That's the much more difficult problem because we also need, in addition to airstrikes, we need a military on the ground in Syria to take these guys on," Morell, now a CBS News consultant, said Wednesday on "CBS This Morning."
"The only military around is [Syrian President Bashar] Assad's military, and as you know, we're fighting Assad as well."
Mr. Obama has repeatedly called for Assad, who has been accused of using chemical weapons against his own people, to step down amid more than three years of violence.
While Morell said the best course of action would be to persuade Russia and Iraq to pressure Assad to leave office and work with new leadership in Syria who could help fight ISIS, that may not be realistic. Assad remains popular among many Syrians, and there's no reason to think he'll be leaving his office anytime soon.
"If that doesn't work, I think we need to rethink our strategy vis-à-vis Assad, yes," Morell said.
Cameron on Monday proposed new laws that would give police the power to seize the passports of Britons suspected of having traveled abroad to fight with terrorist groups.
The U.S. began launching airstrikes against ISIS targets in Iraq last month, and both the U.S. and Britain have been making humanitarian aid drops to besieged minority groups there. Cameron said that he hadn't ruled out joining the U.S. in airstrikes, but added that the priority was to support those already fighting the militants on the ground.
"We need to show real resolve and determination, we need to use every power and everything in our armory with our allies - with those on the ground - to make sure we do everything we can to squeeze this dreadful organization out of existence," Cameron told the British network ITV.
U.S. officials say Mr. Obama is reluctant to delve into Syria's quagmire on his own. He's expected to use some of his discussions in Wales to try to build a coalition that could join him in confronting ISIS through a combination of military might, diplomatic pressure and economic penalties.
Mr. Obama and Cameron visited a local school Thursday morning, where they greeted students learning about NATO before sitting down for a private meeting. Later, the two met with their counterparts from France, Germany and Italy to discuss the crisis in Ukraine. In a show of Western solidarity, new Ukrainian President Petro Poroshenko also joined the discussion.
Ukraine and Russia have been locked in a standoff for months, with pro-Moscow forces stirring instability in eastern Ukrainian cities. On the eve of the NATO summit, Russia and Ukraine said they were working on a deal to halt the fighting, but Western leaders expressed skepticism - noting it wasn't the first attempt to end the deadly conflict.
A centerpiece of the NATO summit was to be the announcement of the rapid response force. Officials said the alliance could position at least 4,000 forces and military equipment in the Baltics and elsewhere in Eastern Europe.
"We must use our military to ensure a persistent presence in Eastern Europe, making clear to Russia that we will always uphold our Article 5 commitments to collective self-defense," Mr. Obama and Cameron wrote.
Under Article 5 of the NATO charter, an attack on one member state is viewed on an attack on the whole alliance. Obama reiterated his support for that principle Wednesday during a visit to Estonia, one of the newer NATO members set on edge by Russia's provocations.