line and a game changer. he now sees that as a green light. that is the word of the president of the united states can no longer be taken seriously. >> reporter: mccain says it's time to take military action. the chairman of the joint chiefs of staff, general martin dempsey cautions the use of military force can change the military balance, but cannot resolve the underlying and historic, ethnic, religious issues fueling the conflict. >> you are checking the pictures on youtube? >> yes. >> reporter: in washington, the u.s. representative of the syrian opposition studies the gruesome photos of families killed in the attack. there should be consequences, he says. >> you need the credible threat of the force. they take that seriously. he's been given all the wrong signals in the past. all those strong signals meant