In his address to the nation almost two weeks ago, President Obama promised to use force against the armies of Islamic State "wherever they are," and he specifically mentioned Syria. But Monday night's airstrikes in that country came sooner and with more force than expected, targeting not only Islamic State but also the Khorasan Group, an Al Qaeda offshoot thought to be plotting attacks on Americans. 
 
 This major offensive raises questions about whether the United States (and a few Arab allies) are planning a prolonged air campaign in a country whose leadership did not invite intervention. Coupled with his successful lobbying of Congress to spend hundreds of millions of dollars to train supposedly moderate Syrian rebels, the airstrikes mark a major reversal for Obama. 
 
 Until recently he has assiduously resisted American entanglement in Syria's civil war, and for good reason. The conflict pits President Bashar Assad, a secular dictator with innocent blood on his hands, against an assortment of opponents whose division into moderate and extremist factions isn't nearly so neat or stable as some advocates of U.S. intervention suppose. 
 
 Obama changed his mind about intervention in Syria for the same reason he decided to launch airstrikes in Iraq and augment the U.S. military presence in that country: a sickeningly swift sequence of events in which Islamic State fighters routed Iraqi forces, terrorized Christians and other minorities and seemed poised to attack Baghdad. Obama also was influenced, understandably, by the horrific beheadings of two American journalists. 
 
 The result was his promise of a long-term campaign to "degrade and ultimately destroy" Islamic State. Obama said that wouldn't require U.S. combat forces. But if the threat posed by Islamic State justifies a rethinking of Obama's aversion to intervention in Syria, might it not also incline him to change his view about "no boots on the ground"? Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, has said that if necessary he would recommend that U.S. military "advisors" accompany Iraqi troops into battle. 
 
 The airstrikes mark a major reversal for Obama. 
 
 We find that prospect troubling. Islamic State is a heinous group, a threat to U.S. interests (though not, as far as we know, to the U.S. homeland) and a threat to the rights of those in the Middle East whom it despises as infidels. But is the threat serious enough to justify an ever-escalating role for the U.S. military in Syria and Iraq? Does the U.S. have a clear strategy and achievable aims? The case has yet to be made. 
 
 Follow the Opinion section on Twitter @latimesopinion ||||| President Barack Obama is doubling down on his strategy to combat Islamic State in the face of rising calls from domestic allies and critics alike for a more aggressive campaign against the extremist group. 
 
 In the wake of the deadly Islamic State terrorist attack on Paris, Obama again ruled out on Monday dispatching a major U.S. ground force to Syria and Iraq, saying that would be a “serious mistake” and would push the nation along an unsustainable path of committing to the long-term occupation of countries across the Middle East and North Africa. 
 
 Instead, he made a plea for patience to let military, economic and diplomatic pressure work, even as he promised to adjust to conditions. 
 
 “There will be an intensification of the strategy that we put forward, but the strategy that we are putting forward is the strategy that ultimately is going to work,” Obama said at a news conference concluding the Group of 20 summit in Turkey, just 300 miles from a main battle zone in Syria. “But as I said from the start, it’s going to take time.” 
 
 On Defensive 
 
 The president became defensive as he was repeatedly questioned by reporters about whether he had underestimated Islamic State, whether his emphasis on diplomacy emboldened the extremists and whether he truly understands the enemy. His exasperation was evident in his response to the third such question posed. 
 
 “All right, so this is another variation on the same question,” he said. “Let me try it one last time.” 
 
 Shrinking the territory the terrorists control, getting local forces trained and equipped to keep them out and resolving the civil war in Syria -- “that ultimately is going to be what’s going to make a difference,” he said. “And it’s going to take some time, but it’s not something that at any stage in this process have we not been aware needs to be done.” 
 
 Obama’s critics in Congress have said that’s not enough, and their calls for more robust action have grown louder since the attacks in Paris on Friday that killed at least 129 people and wounded more than 300 others. 
 
 Ground Forces 
 
 Senator Lindsey Graham of South Carolina, a member of the Armed Services Committee and a Republican presidential candidate, has long been pushing for a no-fly zone in Syria. He now says American troops should join Arab and Turkish forces in ground combat in Syria against Islamic State, also known by the acronyms ISIL and ISIS. 
 
 “Let’s use their armies in a smart way and integrate our forces within a regional army” for a ground campaign to supplement airstrikes, Graham said Monday on MSNBC. 
 
 Democratic Senator Dianne Feinstein of California, usually an administration ally, joined the call for more force beyond the several dozen special operations advisers Obama has said the U.S. was deploying in Syria after the failure of a Defense Department program to train “moderate” rebels. 
 
 “I can’t tell you how many troops on the ground we need,” Feinstein said in a separate interview on MSNBC. “But we certainly need more than 50 special ops, and we need the ability to really make a difference on the ground.” 
 
 R. Nicholas Burns, who was Undersecretary of State under President George W. Bush, said Obama should step up the air campaign against Islamic State and arms shipments to groups in the region opposed to the terrorists. 
 
 Sending Weapons 
 
 “We can and should provide much greater conventional weaponry to the Syrian Kurds, to the Peshmerga and to some of the Arab Sunni,” Burns, who is now a professor at Harvard University’s Kennedy School of Government, said in an interview. “We’ve done so little of that. We’ve been so tentative for four years now.” 
 
 Obama lit into his domestic critics, particularly some Republicans running in the 2016 presidential campaign who’ve called for a more robust military campaign against Islamic State. 
 
 “Some of them seem to think that if I were just more bellicose in expressing what we’re doing that that would make a difference because that seems to be the only thing that they’re doing, is talking as if they’re tough,” Obama said. 
 
 Republican critics have offered few concrete alternatives, he said, with the exceptions of sending in ground forces or establishing no-fly zones, moves that open up a “whole set of questions that have to be answered.” 
 
 The president grew visibly irritated with repeated questions during his news conference about whether he should act more decisively or faster to destroy Islamic State. He said he is aware his approach doesn’t offer the satisfaction of a "neat headline" or an immediate solution. 
 
 “What I’m not interested in doing is posing or pursuing some notion of ‘American leadership’ or ‘America winning”’ that has “no relationship to what is actually going to work,” he said. 
 
 ‘Face of Evil’ 
 
 Obama called Islamic State “the face of evil” and insisted the U.S. and its allies are shrinking its hold in Syria and Iraq even as the group has demonstrated its ability to commit violence beyond the region. 
 
 The attacks in Paris last week were “a terrible and sickening setback” in what will be a long campaign against Islamic State, Obama said Monday, shortly after meeting with leaders of European countries at a summit in Turkey. 
 
 What won’t work, he said, is sending thousands more U.S. troops into the fight. 
 
 “We would see a repetition of what we’ve seen before, which is if you do not have local populations that are committed” to helping combat extremism, Obama said, the terrorists “resurface, unless we are prepared to have a permanent occupation of these countries.” 
 
 Obama’s strategy may be under pressure as well from some allies and other players, including Russia, which also is conducting airstrikes in Syria. Like France, Russia has been a target of Islamic State terrorism. A Russian passenger jet was blown out of the sky over Egypt in an attack blamed on the group. 
 
 While French President Francois Hollande, like Obama, has ruled out deploying ground troops in Syria in the midst of a civil war, there were signs that last Friday’s terrorist attack is spurring an accommodation with Russian President Vladimir Putin, who backs Syrian President Bashar al-Assad and has so far resisted U.S. and European demands that he depart eventually as part of a transition. 
 
 In a speech to a rare joint session of parliament in Versailles, Hollande said he would call Putin as well as Obama “to unite our efforts and seek a solution.”
– The New York Times editorial board thinks President Obama has the US blundering into a new war with the expanded airstrikes in Syria. Before the US gets any deeper into the operation, the president should open this up for a full debate in Congress, says the editorial. It's also "puzzling" that in preparing the nation on Sept. 10 for these airstrikes, Obama said nothing about the Khorasan group that is suddenly Public Enemy No. 1. "There isn’t a full picture—because Mr. Obama has not provided one—of how this bombing campaign will degrade the extremist groups without unleashing unforeseen consequences in a violent and volatile region," says the editorial. "In the absence of public understanding or discussion and a coherent plan, the strikes in Syria were a bad decision." Agree: The airstrikes are a "major reversal" for a president who opposed intervention in Syria for so long, writes the Los Angeles Times in an editorial. Can we trust that he won't reverse himself on ground troops, too? Yes, ISIS and the Khorasan group pose threats to US interests, "but is the threat serious enough to justify an ever-escalating role for the US military in Syria and Iraq?" asks the editorial. "Does the US have a clear strategy and achievable aims? The case has yet to be made." Disagree: The Wall Street Journal editorial board not only applauds the airstrikes but thinks US ground troops should be ready to move quickly. If the mission is to succeed, and it must, they'll be needed to direct airstrikes as militants hide in populated areas. "No US President should ever start a war he doesn't intend to win, and wars rarely go as smoothly as advertised in advance," concludes the editorial. "Now that he has attacked ISIS, Mr. Obama must show that America is the strong horse."