The president warned against inaction because the world is "war weary."
"There is a certain weariness, given Afghanistan," he said, ahead of a Cabinet room meeting with the leaders of Estonia, Lithuania and Latvia. "There is a certain suspicion of any military action post-Iraq."
"I very much appreciate that... It’s important for us to recognize that when over a thousand people are killed, including hundreds of innocent children, through the use of a weapon that 98 or 99 percent of humanity says should not be used even in war, and there is no action, then we’re sending a signal… That is a danger to our national security."
Obama said that he was in close consultation with Congress and insisted that any action taken would be limited in focus and would not involve "boots on the ground."
In his statement earlier Friday, Secretary Kerry was both more expansive and more forceful, laying out in detail the evidence that Syrian President Bashar al-Assad's regime called for chemical weapons strikes against opposition forces.
"Well, we know that the Assad regime has the largest chemical weapons program in the entire Middle East," Kerry said. "We know that the regime has used those weapons multiple times this year and has used them on a smaller scale, but still it has used them against its own people, including not very far from where last Wednesday’s attack happened."
Kerry blamed chemical weapons killed 1,429 people, including 426 children, in a single attack on the morning of August 21.
"This is the indiscriminate, inconceivable horror of chemical weapons," Kerry said. "This is what Assad did to his own people."
The secretary argued the credibility of the United State is on the line, and that if no action is taken against Assad's regime, other countries would defy international norms with impunity.
"It matters because if we choose to live in a world where a thug and a murderer like Bashar al-Assad can gas thousands of his own people with impunity, even after the United States and our allies said no, and then the world does nothing about it, there will be no end to the test of our resolve and the dangers that will flow from those others who believe that they can do as they will," Kerry said.