What complicates the matter is how some of the Syrian opposition is affiliated with al Qaeda.
"One of the challenges that we have is that some of the most effective fighters within the opposition have been those who, frankly, are not particularly friendly toward the United States of America. And arming them willy-nilly is not a good recipe for meeting American interests over the long term," Obama said.
He also spoke of avoiding a sectarian Islamic quagmire between Shiites and Sunnis in Syria.
The United States has learned some hard lessons from the Iraq and Afghanistan wars, he said.
"We know what it's like to rush into a war in the Middle East without having thought it through. And there are elements within the Middle East who see this entirely through the prism of a Shia/Sunni conflict and want the United States to simply take the side of the Sunnis. And that I do not think serves American interests," Obama said.
"Now on the other side there are folks who say, 'You know we are so scarred from Iraq, we should have learned our lesson, we should not have anything to do with it.'
"Well I reject that view as well because the fact of the matter is that we've got serious interests there and not only humanitarian interests. We can't have a situation of ongoing chaos in a major country that borders a country like Jordan, which in turn borders Israel. And we have a legitimate need to be engaged and to be involved."
Meeting with China on alleged hacking
Last week, Obama met with new Chinese President Xi Jinping.
The U.S. president broached the serious allegations of hacking against China.
"You know, when you're having a conversation like this I don't think you ever expect a Chinese leader to say, 'You know what? You're right. You caught us red-handed. We're just stealing all your stuff and every day we try to figure out how we can get into Apple,'" Obama said.
But, he added: "We had a very blunt conversation about cybersecurity" with the Chinese president.
Ben Bernanke on way out?
Asked if he is going to reappoint Ben Bernanke to a third term as Federal Reserve chairman, Obama sidestepped a direct answer, opening the door to speculation that Bernanke's tenure may be ending.
"He's already stayed a lot longer than he wanted, or he was supposed to," Obama said. "He has been an outstanding partner along with the White House in helping us recover much stronger than, for example, our European partners from what could have been an economic crisis of epic proportions."
Bernanke led the central bank's response to the global financial collapse that began in fall 2007, keeping interest rates at historic lows and shepherding a massive Fed intervention in the government bond market.
He became chairman in February 2006 as an appointee of President George W. Bush. Obama appointed Bernanke to a second term in 2010. Bernanke's term expires on January 31, 2014.