In the wake of Friday's terrorist attacks in Paris, many political leaders, both in the United States and abroad, on the left and the right, called for a rethinking of the world's policies in taking on ISIS.

But the man with the most influence, President Barack Obama, is not looking to change course.

In a news conference in Antalya, Turkey, where he was attending a G20 meeting, Obama repeatedly rejected criticism of his approach to fighting ISIS, refused to say he had underestimated the group and pledged to continue his current policies.

Despite calls from some Republicans to send tens of thousands of troops to fight ISIS in Iraq and Syria, Obama argued that the U.S. experience after the Iraq war showed the flaws of such an approach.

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Obama's doubling down is an illustration that he is committed to the foreign policy vision that helped him get elected president.

While on other issues Obama has wavered or switched positions during his administration (his acceptance of a mandate for people to get health insurance after opposing it in the campaign is perhaps the most prominent example), the president seems determined to avoid leaving U.S forces in the middle of a long, protracted battle in the Middle East.

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Twice asked by reporters if he regretted his handling of ISIS as the group gained strength, particularly early last year when the president compared ISIS to a "jv team," a frustrated Obama said there has long been "an acute awareness" from his administration about the dangers of ISIS.

The president even repeated a remark that he made Thursday that was widely criticized in the wake of Paris attacks, arguing that the coalition against the group is already "containing" ISIS in Iraq and Syria, since the insurgent group holds less territory in those two countries than it did last year.

Throughout the press conference, the president repeated his core approach to ISIS: airstrikes to target the group's strongholds in Iraq and Syria; a limited use of American troops (the U.S has about 3,500 military troops in Iraq to fight ISIS there and last month deployed 50 special forces officers to Syria); emphasis on diplomacy to end the civil war in Syria and the world welcoming refugees from Syria. The United States has pledged to accept 10,000 Syria refugees over the next year.

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Obama urged both the U.S. and other countries to continue to accept Syrian refugees, even as several American governors announced they would be unwilling to do so in the wake of the Paris attacks. And Obama, while not calling them out by name, angrily blasted the sentiments of Republican presidential candidates such as Texas. Sen. Ted Cruz and ex-Florida Gov. Jeb Bush, who have suggested the U.S. should only accept refugees who are Christian.

"When I hear political leaders suggesting that there would be a religious test for which person who is fleeing from a war-torn country is admitted, when some of those folks themselves come from families who benefited from protection when they were fleeing political persecution, that's shameful, that's not American," Obama said.

Speaking of his broader approach to fighting ISIS, Obama said, "We have the right strategy and we're going to see it through."

But many argue that the U.S. is already now deeply involved in another Middle Eastern conflict already and that the president needs to rethink his long-held views. Bill Kristol, a prominent Republican who runs the conservative Weekly Standard, said over the weekend that the U.S. should consider sending up to 50,000 troops to fight ISIS, while even Democrats, such as California congressman Adam Schiff, the top Democrat on the House Intelligence Committee, said the president's approach is too limited.

French President Francois Hollande has used aggressive, bellicose language in saying his country is at war with ISIS, a tone Obama has largely avoided. In Saturday's Democratic presidential debate, Hillary Clinton, while defending Obama's policy on ISIS, rejected his word choice.

"It cannot be contained, it must be defeated," Clinton said of ISIS.

"Presidents would prefer to try a little and, only if it proves insufficient, to try a little more," Kori Schake, a Hoover Institution fellow, wrote in a piece published by Foreign Policy.

"This is exactly what Obama has been doing in Iraq and Syria, ordering a few hundred trainers here and a smattering of airstrikes and special operations troops there. But gradual escalation in warfare sends the wrong message to enemies — it telegraphs the limitations countries place on themselves, encouraging those enemies to keep fighting. And it is clearly not how Hollande wants to approach the fight."