As millions of americans head into a holiday weekend right now at the white house, the president is making an historic decision. He is deciding if america will launch a strike on syria, possibly... See More
As millions of americans head into a holiday weekend right now at the white house, the president is making an historic decision. He is deciding if america will launch a strike on syria, possibly within the next 48 hours. The u.N. Weapons inspectors are pulling out of syria by midday tomorrow, which clears the way and the administration argued publicly today that syria's president is a thug and a murderer and his use of chemical weapons endangers not only the syrian people, but the united states and the world. Still a new poll says half of americans wonder if a military strike will work, or maybe even backfire. Team coverage, tonight the crisis in syria and wree begin with martha raddatz in washington with what the white house says something must be done. Reporter: In the situation room this morning, the president's national security team huddled to discuss options in syria, and this afternoon, his secretary of state presented the most forceful case for a military strike to date. What we choose to do or not do, matters in real ways to our own security. Some cite the risk receive doing things. We need to ask, what is the risk of doing nothing? Reporter: Calling syria's president a thug and murderer who gassed his own people while they slept. Human intelligence, satellite tracking of rockets, communications intercepts and orders to syrian troops. We know that the syrian regime elements were told to prepare for the attack by putting on gas masks and taking precautions associated with chemical weapons. Reporter: But it's the images and the stories from the survivors that are clearly the most compelling. And that number. 1,429. Killed, including those 426 children. The american people are tired of war. Believe me, I am too. But fatigue does not absolve of us of our responsibility. And history would judge us all extraordinarily harshly if we turned a blind eye to a dictator's wanton use of weapons of mass destruction. Reporter: Within hours of kerry, the president spoke, clearly concerned that the people abroad, the people at home, and congress fear another long-term conflict like iraq or affingts. We're not considering any eep ended commitment. We're not considering any boots on the ground approach. While the president insists it would not be an open-ended commitment, critics say it could be a chronic one. If the u.S. Bombs syria and asad comes back and gases more civilians, the u.S. Would certainly have to go in again and take military action. So what is the best a strike would hope to achieve? I think to prevent and der ter chemical weapons use for a while. For as long as possible. That's what they can hope for here. That's what they're trying to achieve. Martha raddatz standing watch in washington. What about the syrian response tonight? Terry moran in the region for that. Reporter: In damascus today, while us leaders made their case for an attack -- the civil war didn't stop. It didn't even pause. Government artillery pounding away at rebel positions. The shelling hindered u.N. Inspectors as the concluded their investigation. Elsewhere, people just went on with their lives. The lucky ones in cafes, others lining up for bread. But in the palace and the parliament, president bashar al assad and his government remain defiant, and well-fed. "Syria won't surrender," declared the speaker of parliament. And now, another atrocity. What happened here almost defies words. Reporter: The bbc's ian pannell reported from the scene of what appeared to be an incendiary bomb attack, allegedly carried out by a syrian air force jet on a school. They arrived like the walking dead. We don't know for sure what was in the bomb but the injuries and debris suggest something like napalm or thermite. Reporter: The shelling continues, day and night, even amid reports that syrian military bases are being emptied of tanks, missiles, even furniture ahead of the expected u.S.-Lead attack. So the war can go on afterwards. Here in the arab world, this crisis has strengthened assad, he is seen to be defying the u.S. And israel, and that for millions of arabs, is more important than the atrocities he is blamed for. Diane? Thanks so much, terry. Now to remind you about the countries taking sides all around syria, a nation of almost 21 million people. Here's the map. Iran, of course is on syria's side. And so is hezbollah in lebanon. America's key allies are so close, jordan and notably, israel. So let's bring in former combat pilot, and abc news contributor, steve ghanyard. What is the first sign our viewers will have that a strike is under way? I think we'll see a war that starts the same way, where it's night-time in a capital, broipt explosions of light as the tomahawks find their tarkets. Any american forces in peril at that moment? No, the president made it clear no u.S. Military forces will be in peril. They'll be launched from well out to sea. No u.S. Lives will be in danger. And the targets themselves, limited targets over and over again. What does that mean to you? They'll go after the unit that conducted these attacks on the civilians. They know where that unit is. They will punish that unit with military strikes. But they'll also level probably a ministry of defense building, something that's iconic and they'll be able to show the world that the u.S. Has conducted this strike. They want to say to everyone the u.S. Was there and there is accountability. Thank you so much. Turning now to another story, the wildfire that is
This transcript has been automatically generated and may not be 100% accurate.