GWEN IFILL: President Obama marked the first 100 days of his second term today using a news conference to demand action on his agenda, from Guantanamo to guns.
NewsHour correspondent Kwame Holman begins our coverage.
QUESTION: Do you still have the juice to get the rest of your agenda through this Congress?
PRESIDENT PRESIDENT OBAMA: If you put it that way, Jonathan, maybe I should just pack up and go home. Golly.
KWAME HOLMAN: President Obama joked and jabbed in the White House Briefing Room as he pressed the point that he's no lame duck and that he will keep pushing his priorities.
PRESIDENT OBAMA: We understand that we're in a divided government right now. The Republicans control the House of Representatives. In the Senate, this habit of requiring 60 votes for even the most modest piece of legislation has gummed up the works there.
Despite that, I'm actually confident that there are a range of things that we are going to be able to get done.
KWAME HOLMAN: For instance, he said he believes Congress will approve sweeping immigration reform. And he insisted he hasn't given up on closing the prison at Guantanamo, Cuba, as he vowed to do in his first presidential campaign.
PRESIDENT OBAMA: I think it is critical for us to understand that Guantanamo is not necessary to keep America safe. It is expensive. It is inefficient. It hurts us in terms of our international standing. It lessens cooperation with our allies on counterterrorism efforts. It is a recruitment tool for extremists. It needs to be closed.
KWAME HOLMAN: Congress has balked at transferring detainees to the mainland U.S., but more than half of the 166 captives now are waging a hunger strike for better conditions and an end to years of legal limbo.
PRESIDENT OBAMA: I don't want these individuals to die. Obviously, the Pentagon is trying to manage the situation as best as they can.
But I think all of us should reflect on why exactly are we doing this? Why are we doing this? I'm going to go back at this. I've asked my team to review everything that's currently being done in Guantanamo, everything that we can do administratively. And I'm going to reengage with Congress to try to make the case that this is not something that's in the best interest of the American people.
KWAME HOLMAN: Likewise, the president said it's not in the country's best interest to keep the across-the-board spending cuts known as the sequester.
PRESIDENT OBAMA: It's slowed our growth. It's resulting in people being thrown out of work. And it's hurting folks all across the country.
And the fact that Congress responded to the short-term problem of flight delays by giving us the option of shifting money that's designed to repair and improve airports over the long term to fix the short-term problem, well, that's not a solution.
KWAME HOLMAN: And that was a recurring theme, Mr. Obama arguing that the failure to address Guantanamo or budget problems or gun violence lies squarely on Congress' doorstep, as he told ABC News’ Jonathan Karl.
PRESIDENT OBAMA: Jonathan, you seem to suggest that somehow these folks over there have no responsibilities and that my job is to somehow get them to behave. That's their job.
KWAME HOLMAN: By the same token, the president accused Republicans in Congress and statehouses of obstructing his health care reform law. He acknowledged some glitches, but said they don't affect most people.
PRESIDENT OBAMA: Despite all the hue and cry and sky is falling predictions about this stuff, if you've already got health insurance, then that part of Obamacare that affects you, it's pretty much already in place. And that's about 85 percent of the country.
What is left to be implemented is those provisions to help the 10 to 15 percent of the American public that is unlucky enough that they don't have health insurance.
KWAME HOLMAN: While much of the 48-minute White House news conference dealt with domestic policy and tensions with Congress, the questions also turned abroad, the main focus, the ongoing conflict in Syria and signs that Bashar al-Assad may have used chemical weapons against the rebels.
President Obama indicated he's ready to consider military options if the case is proved.
PRESIDENT OBAMA: What we now have is evidence that chemical weapons have been used inside of Syria, but we don't know how they were used, when they were used, who used them. We don't have a chain of custody that establishes what exactly happened.
KWAME HOLMAN: In short, he said the American people and the world expect him to make sure he's got the facts before acting.
PRESIDENT OBAMA: If we end up rushing to judgment without hard, effective evidence, then we can find ourselves in a position where we can't mobilize the international community to support what we do. There may be objections even among some people in the region who are sympathetic with the opposition if we take action. So it's important for us to do this in a prudent way.
KWAME HOLMAN: Late today, The Washington Post reported the president now is preparing to send lethal weaponry to the Syrian rebels. The account said a final decision is likely within weeks.
As for another security threat, the Boston bombings, the president said so far it appears the Department of Homeland Security and the FBI did their jobs in the months leading to the attacks.
PRESIDENT OBAMA: The FBI investigated that older brother. It's not as if the FBI did nothing. They not only investigated the older brother; they interviewed the older brother. They concluded that there were no signs that he was engaging in extremist activity. So, that much, we know.
KWAME HOLMAN: Still, the president promised a thorough review of whether sensitive intelligence was missed.